[4.7.0] Add user to room on "Click to Join!" button press

Description:

Fix https://github.com/RocketChat/Rocket.Chat/issues/19420

Steps to reproduce:

1. Start a new Jitsi call in a channel or discussion (logged in as a member of the room). Then, access the room as another user and press the "Click to Join!" button. Expected behavior: the user should join the room (if they're not already a member).
2. Access a discussion inside a channel (public room). Expected behavior: If the user is not a member of the discussion, a "Join" button should be displayed in the message box.

Expected behavior:

Clicking the button should open the video.

Actual behavior:

I click the button and nothing happens.

Server Setup Information:

• Version of Rocket.Chat Server: 4.7.0
• Operating System: Ubuntu 20.04.4 LTS
• Deployment Method: tar
• Number of Running Instances: 1
• DB Replicaset Oplog:
• NodeJS Version: v14.19.1
• MongoDB Version: 5.0.8

Client Setup Information

Desktop App or Browser Version: Chrome and Desktop App for Windows
Operating System: Windows

Additional context

none

Relevant logs:

none

Start by tracing the "Click to Join!" button flow for Jitsi calls and the "Join" button flow in discussion message boxes. Verify the room-membership behavior for non-members and confirm that clicking the call button opens the video and displays the Join action when appropriate.