Test Workflow Trigger is flaky

### Body The suite of tests in TestWorkflowTrigger regarding the async io seems pretty flaky - it keeps on failing randomly and we keep on adding more tests as flaky. We likely should address it more generically and implement better harness for those tests. The tests are in `tests/triggers/test_external_task.py` Example failure case: https://github.com/apache/airflow/actions/runs/10158045390/job/28089723094#step:7:7069 ```python ____________ TestWorkflowTrigger.test_task_workflow_trigger_skipped ____________ self = <tests.triggers.test_external_task.TestWorkflowTrigger object at 0x7fc461e60d30> mock_get_count = <MagicMock name='_get_count' id='140481721540768'> @mock.patch("airflow.triggers.external_task._get_count") @pytest.mark.asyncio async def test_task_workflow_trigger_skipped(self, mock_get_count): mock_get_count.side_effect = mocked_get_count trigger = WorkflowTrigger( external_dag_id=self.DAG_ID, execution_dates=[timezone.datetime(2022, 1, 1)], external_task_ids=[self.TASK_ID], skipped_states=self.STATES, poke_interval=0.2, ) gen = trigger.run() trigger_task = asyncio.create_task(gen.__anext__()) fake_task = asyncio.create_task(fake_async_fun()) await trigger_task > assert fake_task.done() # confirm that get_count is done in an async fashion E AssertionError: assert False E + where False = <built-in method done of _asyncio.Task object at 0x7fc44fd4a4a0>() E + where <built-in method done of _asyncio.Task object at 0x7fc44fd4a4a0> = <Task pending name='Task-11' coro=<fake_async_fun() running at /opt/airflow/tests/triggers/test_external_task.py:482> wait_for=<Future finished result=None>>.done ``` ### Committer - [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.