Key the executor-events transaction test by TaskInstanceUuid

After the attempt-UUID executor event rework, the event buffer is
keyed by TaskInstanceUuid rather than the legacy TaskInstanceKey.
Keying this regression test's event by ti1.key meant the event never
matched a captured task identity and was discarded before reaching
set_state, so the test passed even without the session fix it exists
to guard. Key it the same way the other tests in this file do, and
assert the state actually flips to FAILED before the rollback so a
regression is caught again.

Author: namanjain24-sudo

airflow-core/tests/unit/jobs/test_scheduler_job.py

@@ -850,9 +850,11 @@ def test_process_executor_events_sets_state_in_callers_transaction(self, dag_mak
         job_runner = SchedulerJobRunner(Job(), executors=[executor])
         job_runner.scheduler_dag_bag = mock.MagicMock()
         job_runner.scheduler_dag_bag.get_dag_for_run.side_effect = Exception("failed")
-        executor.event_buffer[ti1.key] = State.FAILED, None
+        executor.event_buffer[TaskInstanceUuid(ti1.id)] = State.FAILED, None
 
         job_runner._process_executor_events(executor=executor, session=session)
+        ti1.refresh_from_db(session=session)
+        assert ti1.state == TaskInstanceState.FAILED
         session.rollback()
 
         ti1.refresh_from_db(session=session)