test(celery): diag — fail fast on broker connect

So the py3.7-container kombu hang reveals its real exception instead of
sleeping forever inside retry_over_time.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: sl0thentr0py

tests/integrations/celery/integration_tests/test_celery_beat_cron_monitoring.py

@@ -23,6 +23,12 @@ def celery_config():
         "task_always_eager": False,
         "task_create_missing_queues": True,
         "task_default_queue": f"queue_{os.getpid()}",
+        # DIAG (py3.7 container hang): fail fast on broker connect so the
+        # actual exception surfaces instead of looping forever in
+        # kombu.retry_over_time.
+        "broker_connection_retry": False,
+        "broker_connection_max_retries": 1,
+        "broker_connection_timeout": 2,
     }