Fix act-edit descending query

arkindex/documents/api.py

@@ -93,8 +93,7 @@ class ActEdit(RetrieveAPIView):
     def get_object(self):
         act = super().get_object()
         act.parent_elements = Element.objects.get_ascending_paths(act.id)
-        act.child_elements = Element.objects.get_descending(act.id).exclude(
-            paths__element__type=ElementType.Transcription)
+        act.child_elements = Element.objects.get_descending(act.id).exclude(type=ElementType.Transcription)
         return act