Feature requets: toggle to open backup call service instead, if Teams is down

[pablokvitca]

In the event Teams cannot be used at all (service could be offline), it would be hard to contact the student and start a call on an alternative option. We should have the option to toggle a "Back up call method".
For example, if using Zoom as the backup, we might need to send the student a notification with the link to the Zoom call.