refactor: pre-fill show and timeslot data on note creation

If notes are created through subroutes some of the data necessary to
create a note is already available through the route data and doesn’t
need to be passed as part of the request body anymore.

program/views.py

@@ -709,7 +709,8 @@ class APINoteViewSet(viewsets.ModelViewSet):
             return Response(status=status.HTTP_400_BAD_REQUEST)
 
         serializer = NoteSerializer(
-            data=request.data, context={"user_id": request.user.id}
+            data={"show": show_pk, "timeslot": timeslot_pk} | request.data,
+            context={"user_id": request.user.id},
         )
 
         if serializer.is_valid():