When developing the app client Pau Ferrer has noticed that we are not retrieving the scale used (we get the id, but we need the scale elements).
We should:
- Extend the WS to allow plugins to return additional data via a callback (get_config_for_external()) like we did for database or assignment
- Or create a new generic WS to return scales information based on id "core_grades_get_scale" (the problem here is that there is no way to validate if the user can see the scale or not because they are no-context/permission based).