* Add shared `removeCurrentCall` function to `DefaultActiveCallManager`
This centralises the shared call cancellation logic
* Add regression test for the issue
* Make sure the existing iterations of `flatMapLatest` in `observeRingingCall` get cancelled when the active call is null or not ringing anymore by passing null values, then filtering them out
Previously these kept running even if the `activeCall` was no longer valid
* Move the `timedOutCallJob` cancellation inside `removeCurrentCall` too
10bf5f1c8c