How can i change the user attar in plugin

You’ve created the model with the same name in ./plugins/auth-wechat-minprogram, which is wrong.
You should use extensions if you want to modify some the plugin’s files.

  1. Create the file in: ./extensions/users-permissions/models/User.settings.json,
  2. Copy the content from ./node_modules/strapi-plugin-users-permissions/models/User.settings.json to the newly created file
  3. Now you can modify the file in ./extensions/users-permissions/models/User.settings.json and add new fields.