Participant leave notification.

[ThilinaV98]

1. If a participant in the meeting closes his browser and leaves the meeting, it will show that he is in the meeting, but he is not actually in the meeting.
2. If a participant who has the camera turned on in the meeting closes his browser and leaves the meeting, the camera freezes and shows that he is in the meeting, but he is not actually in the meeting.
3. If a participant leaves the meeting, a notification will not be displayed.

[jibon57]

Clearing status of users may take few seconds. This is expected behavior.