Close the conversation when RC detects that the widget has closed (using Ritik's new feature)

[ear-dev]

The room needs to be closed.

• no open conversations with an agent
• no longer waiting in the queue (if you were waiting in the queue)

[ear-dev]

• Do not use in mobile. This is because of the way mobile users might bounce around the app during a live chat, and moving away from the chat is just like closing the tab (web view)
• Handle two tabs..... do not close chat until tab count == 0.

[itzzritik]

PR Raised: WideChat/Rocket.Chat - PR#1039
Total 3 PRs (all mentioned in the above PR)☝️

Linked Issue: WideChat/Rocket.Chat - Issue#838