Replace focus_room_filter dispatch by Action.OpenSpotlight

[florianduros]

This PR removes the focus_room_filter action and replaces it by Action.OpenSpotlight.

1. focus_room_filter is fired when KeyBindingAction.FilterRooms is triggered:
   

   element-web/src/components/structures/LoggedInView.tsx

   Lines 503 to 508 in 4b9382f

   	case KeyBindingAction.FilterRooms:
   	dis.dispatch({
   	action: "focus_room_filter",
   	});
   	handled = true;
   	break;

2. Which is handled by RoomSearch, to directly open the spotlight:
   

   element-web/src/components/structures/RoomSearch.tsx

   Lines 27 to 43 in 4b9382f

   	public componentDidMount(): void {
   	this.dispatcherRef = defaultDispatcher.register(this.onAction);
   	}
   	public componentWillUnmount(): void {
   	defaultDispatcher.unregister(this.dispatcherRef);
   	}
   	private openSpotlight(): void {
   	defaultDispatcher.fire(Action.OpenSpotlight);
   	}
   	private onAction = (payload: ActionPayload): void => {
   	if (payload.action === "focus_room_filter") {
   	this.openSpotlight();
   	}
   	};

3. We can directly ditch focus_room_filter and opens the spotlight:
   

   element-web/src/components/structures/LoggedInView.tsx

   Lines 503 to 506 in 1aba639

   	case KeyBindingAction.FilterRooms:
   	dis.fire(Action.OpenSpotlight);
   	handled = true;
   	break;