update backend/dvadmin/system/views/message_center.py.

消息中心模板类型是按角色、公告、部门时不返回用户信息，系统用户数据量过多时接口查询很慢

Signed-off-by: star <it_gjl@sina.com>

backend/dvadmin/system/views/message_center.py

@@ -36,6 +36,8 @@ class MessageCenterSerializer(CustomModelSerializer):
         return serializer.data
 
     def get_user_info(self, instance, parsed_query):
+        if instance.target_type  in (1,2,3):
+            return []
         users = instance.target_user.all()
         # You can do what ever you want in here
         # `parsed_query` param is passed to BookSerializer to allow further querying
@@ -106,6 +108,8 @@ class MessageCenterTargetUserListSerializer(CustomModelSerializer):
         return serializer.data
 
     def get_user_info(self, instance, parsed_query):
+        if instance.target_type  in (1,2,3):
+            return []
         users = instance.target_user.all()
         # You can do what ever you want in here
         # `parsed_query` param is passed to BookSerializer to allow further querying