Not Allowed on discussion

Description:

There is a bug in discussions. When an user is invited to join a discussion and He is NOT a member of the channel where the discussion was created, an error occurs with the following message: NOT ALLOWED

Steps to reproduce:

1. Create a discussion on a channel
2. Invite a user outside the parent channel to the discussion
3. the invited user gets a red "not allowed" sign every time he rejoins the discussion

Server Setup Information:

• Version of Rocket.Chat Server: 4.8.0
• Operating System: Ubuntu 20.04.4 LTS
• Deployment Method: ubuntu
• Number of Running Instances: 1
  -Versión de motor de aplicaciones: 1.32.0
  -Versión de nodo: v14.19.3
  -MongoDB 5.0.8 / wiredTiger (oplog Habilitada)

Client Setup Information

• Desktop App: 3.8.7
• Browser Version: Google Chrome Versión 102.0.5005.63
• Operating System: windows 10

###Additional data
grupo_con_nahuel :channel where the test user is located
discutir con nahuel : discussion created from the channel grupo_con_nahue
discutir con nahuel : discussion created from the channel in which the test user is not part of it

https://user-images.githubusercontent.com/51861356/173429109-ed554385-9070-4b1c-98f6-70617e8f4d0c.mp4

Start by reproducing the discussion invite and rejoin flow using the reported setup, then trace the authorization check applied when a participant is not a member of the parent channel. Done means the invited user can rejoin without the “NOT ALLOWED” error and the behavior is covered by a regression test.