update null event values to empty string in downgrade for migration revision_id d75389605139

[rawwar]

Failure happened while downgrading. This PR fixes it:

self.get_context().run_migrations(**kw)
  File "/usr/local/lib/python3.12/site-packages/alembic/runtime/migration.py", line 623, in run_migrations
    step.migration_fn(**kw)
  File "/usr/local/lib/python3.12/site-packages/airflow/migrations/versions/0135_2_9_0_add_run_id_to_audit_log_table_and_change_event_name_length.py", line 65, in downgrade
    with op.batch_alter_table("log") as batch_op:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/contextlib.py", line 144, in __exit__
    next(self.gen)
  File "/usr/local/lib/python3.12/site-packages/alembic/operations/base.py", line 397, in batch_alter_table
    impl.flush()
  File "/usr/local/lib/python3.12/site-packages/alembic/operations/batch.py", line 115, in flush
    fn(*arg, **kw)
  File "/usr/local/lib/python3.12/site-packages/alembic/ddl/postgresql.py", line 188, in alter_column
    super().alter_column(
  File "/usr/local/lib/python3.12/site-packages/alembic/ddl/impl.py", line 280, in alter_column
    self._exec(
  File "/usr/local/lib/python3.12/site-packages/alembic/ddl/impl.py", line 246, in _exec
    return conn.execute(construct, params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/future/engine.py", line 286, in execute
    return self._execute_20(
           ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1710, in _execute_20
    return meth(self, args_10style, kwargs_10style, execution_options)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/sql/ddl.py", line 80, in _execute_on_connection
    return connection._execute_ddl(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1477, in _execute_ddl
    ret = self._execute_context(
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1953, in _execute_context
    self._handle_dbapi_exception(
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 2134, in _handle_dbapi_exception
    util.raise_(
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/util/compat.py", line 211, in raise_
    raise exception
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1910, in _execute_context
    self.dialect.do_execute(
  File "/usr/local/lib/python3.12/site-packages/sqlalchemy/engine/default.py", line 736, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.IntegrityError: (psycopg2.errors.NotNullViolation) column "event" of relation "log" contains null values

[amoghrajesh]

Looks good

[vatsrahul1001]

We can do something like this

[rawwar]

Failing breeze docs check will be fixed by #51681 .

[rawwar]

merging as failure is unrelated