message: Fix crash when filtering new room list too fast
  Fixes
  We were simply assuming we had a reference to a notification state, which might not be the case if we're between renders.
diff: @@ -240,6 +240,7 @@ export class ListNotificationState extends EventEmitter implements IDestroyable
  this.rooms = rooms;
  for (const oldRoom of diff.removed) {
  const state = this.states[oldRoom.roomId];
  + if (!state) continue; // We likely just didn't have a badge (race condition)
  delete this.states[oldRoom.roomId];
  state.off(NOTIFICATION_STATE_UPDATE, this.onRoomNotificationStateUpdate);
  state.destroy();
  