Add retry to test_priority_used_in_transaction_error_events

Author: hmstepanek

tests/agent_features/test_priority_sampling.py

@@ -63,6 +63,7 @@ def test_priority_used_in_transaction_error_events(first_transaction_saved):
     first_priority = 1 if first_transaction_saved else 0
     second_priority = 0 if first_transaction_saved else 1
 
+    @retry(attempts=5, wait=2)  # This test is flakey so add a retry.
     @reset_core_stats_engine()
     def _test():
         with BackgroundTask(application(), name="T1") as txn: