family: an empty context is {}, not None (#10860)

combo/apps/family/models.py

@@ -46,7 +46,7 @@ class FamilyInfosCell(CellBase):
                                    raise_if_not_cached=not(context.get('synchronous')))
         if response.status_code == 200:
             return {'family': response.json()}
-        return None
+        return {}
 
     def render(self, context):
         self.context = context