Description:

According to this: #17442
and to this: https://github.com/RocketChat/Rocket.Chat/releases/tag/3.3.0

The feature "Add the ability to send Livechat offline messages to a channel" is available. And it is, but it is not working as expected. Not all the private groups are available in the list (search results).

When a private group is specified it is seems it is not saved (because it is not there the next time you open the configuration and because the expected behavior doesn't accour)

Steps to reproduce:

1. Go to Omnichannel configuration
2. Select a department
3. Search the private group to forward the incoming messages when all agents are offline.
4. Not all private groups are available (issue1)
5. The selected private group is not saved after clicking the save button (issue2)

Expected behavior:

1. All the private groups are available for the message forwarding.
2. After clicking the save button and closing the Omnichannel configuration the configuration is saved.
3. The exepected behaviour of this feature is the following:
   When a new incoming Omnichannel message, if all agents of the department are offline, the incoming message is forwarded to the configured private group, so that the agents which are also members of the group are notified in the mobile app! and can see the message, then can somehow start chatting with the "livechat-guest" from the mobile app. In case this is not possible, the agens can go to a workstation to continue with the conversation..

Actual behavior:

Not all groups are available for the message forwarding.
The selected group is not saved.

Server Setup Information:

• Version of Rocket.Chat Server: v3.3.0 and v3.3.3
• Operating System: Ubuntu 18
• Deployment Method: docker
• Number of Running Instances: 1
• DB Replicaset Oplog: enabled
• NodeJS Version: v12.16.1
• MongoDB Version: 4.0.18

Client Setup Information

• Desktop App or Browser Version: both
• Operating System: MacOS

Additional context