fix(notifications) throttle join notifications for 2 seconds

react/features/notifications/actions.js

@@ -170,7 +170,7 @@ const _throttledNotifyParticipantConnected = throttle((dispatch: Dispatch<any>)
 
     joinedParticipantsNames = [];
 
-}, 500, { leading: false });
+}, 2000, { leading: false });
 
 /**
  * Queues the display of a notification of a participant having connected to