Detected SessionStatusNotification and SessionInvitationNotification schemas not in use

[stroncoso-quobis]

Problem description
Detected SessionStatusNotification and SessionInvitationNotification schemas not in use.
The API files must be clean of unused data, big flies require long mantainer reviews, it will be great to keep them clean.

Expected behavior
Remove schemas form BYON-CallHandling API.

Alternative solution
n/a

Additional context
With the inclussion of the webrtc-events API, all notifications and events are described on that API.