Change Details

[ENG-1729](https://linear.app/comm/issue/ENG-1729/update-notifications-dialog-to-handle-threads-correctly) Disables background option in notifications dialog for sidebars, because they can't be moved between tabs anyway. (screenshots in the task)

[ENG-1729](https://linear.app/comm/issue/ENG-1729/update-notifications-dialog-to-handle-threads-correctly) Disables background option in notifications dialog for sidebars, because they can't be moved between tabs anyway.

[ENG-1729](https://linear.app/comm/issue/ENG-1729/update-notifications-dialog-to-handle-threads-correctly) Disables background option in notifications dialog for sidebars, because they can't be moved between tabs anyway. (screenshots in the task)