Allow call events to be logged without a room id (#2937)

Prior to this PR, we assumed that all call events needed a room_id, but
we now have call-based actions that don't need a room_id - for instance,
you can right click a channel and view the notes while not in a call. In
this case, there is no room_id. We want to be able to track these
events, which requires removing the restriction that requires a room_id.

Release Notes:

- N/A