Fix SQLA Mapped type import errors in model classes

[amoghrajesh]

SQLAlchemy requires the Mapped type to be available at runtime when processing
class annotations, but several model files imported it only in TYPE_CHECKING
blocks. This caused NameError exceptions during database initialization. CI broken with error:

  /opt/airflow/airflow-core/src/airflow/dag_processing/dagbag.py:40 DeprecationWarning: airflow.exceptions.AirflowDagCycleException is deprecated. Use airflow.sdk.exceptions.AirflowDagCycleException instead.
  Traceback (most recent call last):
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/util/typing.py", line 306, in eval_name_only
      return base_globals[name]
             ~~~~~~~~~~~~^^^^^^
  KeyError: 'Mapped'
  
  The above exception was the direct cause of the following exception:
  
  Traceback (most recent call last):
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/util.py", line 2221, in _cleanup_mapped_str_annotation
      obj = eval_name_only(mm.group(1), originating_module)
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/util/typing.py", line 314, in eval_name_only
      raise NameError(
          f"Could not locate name {name} in module {module_name}"
      ) from ke
  NameError: Could not locate name Mapped in module airflow.models.taskmap
  
  The above exception was the direct cause of the following exception:
  
  Traceback (most recent call last):
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/util.py", line 2323, in _extract_mapped_subtype
      annotated = de_stringify_annotation(
          cls,
      ...<2 lines>...
          str_cleanup_fn=_cleanup_mapped_str_annotation,
      )
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/util/typing.py", line 156, in de_stringify_annotation
      annotation = str_cleanup_fn(annotation, originating_module)
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/util.py", line 2223, in _cleanup_mapped_str_annotation
      raise _CleanupError(
      ...<4 lines>...
      ) from ne
  sqlalchemy.orm.util._CleanupError: For annotation "Mapped[str]", could not resolve container type "Mapped".  Please ensure this type is imported at the module level outside of TYPE_CHECKING blocks
  
  The above exception was the direct cause of the following exception:
  
  Traceback (most recent call last):
    File "/usr/python/bin/airflow", line 4, in <module>
      from airflow.__main__ import main
    File "/opt/airflow/airflow-core/src/airflow/__main__.py", line 37, in <module>
      from airflow.cli import cli_parser
    File "/opt/airflow/airflow-core/src/airflow/cli/cli_parser.py", line 40, in <module>
      from airflow.cli.cli_config import (
      ...<5 lines>...
      )
    File "/opt/airflow/airflow-core/src/airflow/cli/cli_config.py", line 36, in <module>
      from airflow.utils.cli import ColorMode
    File "/opt/airflow/airflow-core/src/airflow/utils/cli.py", line 39, in <module>
      from airflow.dag_processing.dagbag import DagBag
    File "/opt/airflow/airflow-core/src/airflow/dag_processing/dagbag.py", line 52, in <module>
      from airflow.serialization.serialized_objects import LazyDeserializedDAG
    File "/opt/airflow/airflow-core/src/airflow/serialization/serialized_objects.py", line 69, in <module>
      from airflow.models.dag import DagModel
    File "/opt/airflow/airflow-core/src/airflow/models/dag.py", line 55, in <module>
      from airflow.models.dagrun import DagRun
    File "/opt/airflow/airflow-core/src/airflow/models/dagrun.py", line 63, in <module>
      from airflow.models import Deadline, Log
    File "<frozen importlib._bootstrap>", line 1412, in _handle_fromlist
    File "/opt/airflow/airflow-core/src/airflow/models/__init__.py", line 85, in __getattr__
      val = import_string(f"{path}.{name}")
    File "/opt/airflow/airflow-core/src/airflow/utils/module_loading.py", line 41, in import_string
      module = import_module(module_path)
    File "/usr/python/lib/python3.13/importlib/__init__.py", line 88, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
             ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/opt/airflow/airflow-core/src/airflow/models/deadline.py", line 35, in <module>
      from airflow.models import Trigger
    File "<frozen importlib._bootstrap>", line 1412, in _handle_fromlist
    File "/opt/airflow/airflow-core/src/airflow/models/__init__.py", line 85, in __getattr__
      val = import_string(f"{path}.{name}")
    File "/opt/airflow/airflow-core/src/airflow/utils/module_loading.py", line 41, in import_string
      module = import_module(module_path)
    File "/usr/python/lib/python3.13/importlib/__init__.py", line 88, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
             ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/opt/airflow/airflow-core/src/airflow/models/trigger.py", line 36, in <module>
      from airflow.models.taskinstance import TaskInstance
    File "/opt/airflow/airflow-core/src/airflow/models/taskinstance.py", line 81, in <module>
      from airflow.models.taskmap import TaskMap
    File "/opt/airflow/airflow-core/src/airflow/models/taskmap.py", line 55, in <module>
      class TaskMap(TaskInstanceDependencies):
      ...<216 lines>...
              return all_expanded_tis, total_expanded_ti_count - 1
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/decl_api.py", line 198, in __init__
      _as_declarative(reg, cls, dict_)
      ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/decl_base.py", line 245, in _as_declarative
      return _MapperConfig.setup_mapping(registry, cls, dict_, None, {})
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/decl_base.py", line 326, in setup_mapping
      return _ClassScanMapperConfig(
          registry, cls_, dict_, table, mapper_kw
      )
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/decl_base.py", line 562, in __init__
      self._scan_attributes()
      ~~~~~~~~~~~~~~~~~~~~~^^
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/decl_base.py", line 1022, in _scan_attributes
      collected_annotation = self._collect_annotation(
          name, annotation, base, None, obj
      )
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/decl_base.py", line 1302, in _collect_annotation
      extracted = _extract_mapped_subtype(
          raw_annotation,
      ...<6 lines>...
          expect_mapped=expect_mapped and not is_dataclass,
      )
    File "/usr/python/lib/python3.13/site-packages/sqlalchemy/orm/util.py", line 2330, in _extract_mapped_subtype
      raise orm_exc.MappedAnnotationError(
      ...<3 lines>...
      ) from ce
  sqlalchemy.orm.exc.MappedAnnotationError: Could not interpret annotation Mapped[str].  Check that it uses names that are correctly imported at the module level. See chained stack trace for more hints.
  
  Error: check_environment returned 1. Exiting.
  

Example: https://github.com/apache/airflow/actions/runs/18125410465/job/51580394658

Seems to be caused by: #55954

The reason is that:

---

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[vincbeck]

Thank you!

[kaxil]

Merged