Move XComOperatorLink to serialized_objects as only API server uses it

[amoghrajesh]

#46613 introduced a machinery for operator links to be used via xcoms and task sdk by introducing a new class XComOperatorLink and #47008 moved it to the task sdk. Now that I think about it, it should not reside in the task sdk because it is only used by the DAG processor while serialising / deserialising that too while actually running it (api servrer)

Moving it to serialised_objects instead, where its used.

Plugin present:

Plugin used:

from airflow.plugins_manager import AirflowPlugin
from airflow.sdk.definitions.baseoperatorlink import BaseOperatorLink
from airflow.providers.standard.operators.python import PythonOperator


# define the extra link
class HTTPDocsLink(BaseOperatorLink):
    # name the link button in the UI
    name = "HTTP docs"

    # add the button to one or more operators
    operators = [PythonOperator]

    # provide the link
    def get_link(self, operator, *, ti_key=None):
        return "https://developer.mozilla.org/en-US/docs/Web/HTTP"

# define the plugin class
class AirflowExtraLinkPlugin(AirflowPlugin):
    name = "extra_link_plugin"
    operator_extra_links = [
        HTTPDocsLink(),
    ]

Ran this dag:

from airflow.models.dag import DAG
2from pendulum import datetime
3
4from airflow.providers.standard.operators.python import PythonOperator
5
6
7def handler():
8    print("Hello from the python operator!!")
9
10with DAG(
11    dag_id="extra_links_plugin",
12    start_date=datetime(2022, 11, 1),
13    schedule=None,
14    catchup=False,
15    tags=["extra_links"],
16):
17
18    call_api_simple = PythonOperator(
19        task_id="call_api_simple",
20        python_callable=handler,
21    )

Extra link present:

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[amoghrajesh]

Failures are unrelated to the changes made. Overriding and merging