Send notification to Telegram only on failures

With the increase in the number of spiders sending notification in
Telegram for successfull executions is creating too many noise making it
difficult to see the failures.

data_collection/gazette/monitors.py

@@ -100,4 +100,4 @@ class SpiderCloseMonitorSuite(MonitorSuite):
         ItemValidationMonitor,
     ]
 
-    monitors_finished_actions = [CustomSendTelegramMessage]
+    monitors_failed_actions = [CustomSendTelegramMessage]