Fixed channel chat notifications are not working anymore (#9827)

This PR will fix the following issues that were introduced by the
following pull request #9557.

- Cannot create messages with a mention inside it
- Cannot invite a user
- Cannot accept an invitation

Release Notes:

- Fixed channel chat notifications are not working anymore.

Co-authored-by: Bennet Bo Fenner <53836821+bennetbo@users.noreply.github.com>