Fix db downgrade check condition

[vatsrahul1001]

This PR fixes an issue where downgrading from 3.0.3rc4 to 3.0.2 was failing

The current downgrade logic treats downgrading to 3.0.0 the same as downgrading below 3.0.0, which is incorrect.

ERROR

[2025-07-07T14:54:25.119+0000] {db.py:1210} INFO - Attempting downgrade to revision 29ce7909c52b
Traceback (most recent call last):
  File "/usr/local/bin/airflow", line 10, in <module>
    sys.exit(main())
             ^^^^^^
  File "/opt/airflow/airflow-core/src/airflow/__main__.py", line 55, in main
    args.func(args)
  File "/opt/airflow/airflow-core/src/airflow/cli/cli_config.py", line 48, in command
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/airflow/airflow-core/src/airflow/utils/cli.py", line 112, in wrapper
    return f(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^
  File "/opt/airflow/airflow-core/src/airflow/utils/providers_configuration_loader.py", line 55, in wrapped_function
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/airflow/airflow-core/src/airflow/cli/commands/db_command.py", line 204, in downgrade
    run_db_downgrade_command(args, db.downgrade, _REVISION_HEADS_MAP)
  File "/opt/airflow/airflow-core/src/airflow/cli/commands/db_command.py", line 179, in run_db_downgrade_command
    command(to_revision=to_revision, from_revision=from_revision, show_sql_only=args.show_sql_only)
  File "/opt/airflow/airflow-core/src/airflow/utils/session.py", line 101, in wrapper
    return func(*args, session=session, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/airflow/airflow-core/src/airflow/utils/db.py", line 1225, in downgrade
    raise AirflowException(
airflow.exceptions.AirflowException: Downgrade to revision less than 3.0.0 requires that `ab_user` table is present. Please add FabDBManager to [core] external_db_managers and run fab migrations before proceeding

^ Add meaningful description above
Read the Pull Request Guidelines for more information.
In case of fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragment file, named {pr_number}.significant.rst or {issue_number}.significant.rst, in airflow-core/newsfragments.

[potiuk]

Does it warrant rc5 @kaxil ?

[kaxil]

Does it warrant rc5 @kaxil ?

Yes, there is another bug that @pierrejeambrun has found

[potiuk]

Does it warrant rc5 @kaxil ?

Yes, there is another bug that @pierrejeambrun has found

Ok. I was just about to run the verification :D.. Will wait.

[jedcunningham]

Took us a bit to find the real culprit - thanks past Jed!

[ephraimbuddy]

I don't think it should be 2.10.3 since we have 2.11.0

[ephraimbuddy]

My bad. No migration for 2.11.0

[github-actions]

Backport successfully created: v3-0-test

Status	Branch	Result
✅	v3-0-test