Prior to this fix we had too logic to detect if a user is active or not:
- idle codepath on the frontend
- online user ids on the backend
The frontend solution is not very reliable, and both solution are just trying to be too smart. Making a lot of people questioning why they receive a notification sometimes and sometimes not. This commit removes all this logic and replaces it with a much more simpler logic:
- you can't receive notifications for channel you are actually watching
- we won't play a sound more than once every 3seconds