test: re-decrement expected webhook events (canonical#5894)

Tried to fix in aedb7f9 , but there are two events (start and stop)
per module

tests/integration_tests/reporting/test_webhook_reporting.py

@@ -59,7 +59,7 @@ def test_webhook_reporting(client: IntegrationInstance):
     events = [json.loads(line) for line in server_output]
 
     # Only time this should be less is if we remove modules
-    assert len(events) > 51, events
+    assert len(events) > 50, events
 
     # Assert our first and last expected messages exist
     ds_events = [