startStaleCallsChecker method
checks for stale calls in a room and sends m.terminated
if all the
expires_ts are expired. Call when opening a room
Implementation
void startStaleCallsChecker(String roomId) async {
stopStaleCallsChecker(roomId);
await singleShotStaleCallCheckerOnRoom();
staleGroupCallsTimer[roomId] = Timer.periodic(
staleCallCheckerDuration,
(timer) async => await singleShotStaleCallCheckerOnRoom(),
);
}