fix(queues): now really fix the request notifications

Instead of checking for success, now the correct HTTP response code is
sent by the request API. My previous fix broke the other responses, oops.

Closes #82

Relates #44

The refresh as introduced in my fix for #82 (!89) is reverted, as this
was already done on successful requests.

marietje/queues/api/v1/views.py

@@ -163,7 +163,7 @@ class QueueRequestAPIView(CreateAPIView):
         try:
             playlist_song = queue.request(song, request.user)
         except RequestException as e:
-            return Response(data={"success": False, "errorMessage": str(e)})
+            return Response(status=403, data={"success": False, "errorMessage": str(e)})
 
         request_counter.labels(queue=queue.name).inc()
         return Response(status=200, data=self.serializer_class(playlist_song).data)