[Django Upgrade] Fix one sub-query slicing issue (#10012)

Co-authored-by: John Tordoff <>

Author: Johnetordoff

osf/models/node.py

@@ -981,7 +981,7 @@ def registrations_all(self):
     def osfstorage_region(self):
         from addons.osfstorage.models import Region
         osfs_settings = self._settings_model('osfstorage')
-        region_subquery = osfs_settings.objects.filter(owner=self.id).values('region_id')
+        region_subquery = osfs_settings.objects.filter(owner=self.id).values_list('region_id', flat=True)[0]
         return Region.objects.get(id=region_subquery)
 
     @property