flask_app: api update_gender add returen value

Signed-off-by: binren <zhangbr@elab-plus.com>

flask_app.py

@@ -123,6 +123,7 @@ def update_gender_rate():
     except Exception as e:
         mvp.close()
         return str(e)
+    return '人群性别比列更新完成...'
 
 
 if __name__ == '__main__':