Python API tries to connect to `/api/version` in offline mode

[alahiff]

This of course will never work:

  File "/lustre/home/alahiff/tests/maestro/venv5/lib/python3.11/site-packages/simvue/utilities.py", line 281, in wrapper
    return class_func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lustre/home/alahiff/tests/maestro/venv5/lib/python3.11/site-packages/simvue/config/user.py", line 227, in fetch
    return SimvueConfiguration(**_config_dict)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lustre/home/alahiff/tests/maestro/venv5/lib/python3.11/site-packages/pydantic/main.py", line 214, in __init__
    validated_self = self.__pydantic_validator__.validate_python(data, self_instance=self)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pydantic_core._pydantic_core.ValidationError: 1 validation error for SimvueConfiguration
  Assertion failed, Exception retrieving server version:
 HTTPSConnectionPool(host='nightly.simvue.io', port=443): Max retries exceeded with url: /api/version (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7f4aada6e490>: Failed to establish a new connection: [Errno 101] Network is unreachable')) [type=assertion_error]
    For further information visit https://errors.pydantic.dev/2.10/v/assertion_error

By putting in a print statement it seems that _check_server is being called twice - once with mode set to offline and once with mode set to online.

[wk9874]

Suspect this should be fixed by #672 - will look at both together

[alahiff]

This is now fixed