Add indication of voice call status

[feroom]

I would like to suggest adding an indication of voice call status to the Element-Android app. Specifically, I think it would be very helpful to show the status of a call if the recipient receives an incoming call but does not answer, or the status of a call if the recipient is unavailable. This will help users understand what's happening with the call and avoid unnecessary attempts to contact the recipient if they are busy or unavailable.

I suggest adding a status indicator for voice calls on the call screen, which will display the call status, for example, "Waiting for answer", "Call not answered", "Recipient is busy", "Recipient is unavailable", etc. It would also be great to add an option to send a notification when the call changes to a different status.

This feature, in my opinion, will help make the user experience of using voice calls in the Element-Android app even better.

Thank you!