Webservice mod_assign_get_submission_status doesn't support "All participants"

Prerequisite

1. Moodle mobile app.
2. Your Moodle mobile app should be able to connect to your Moodle website. You can either do the following:
   • Ensure that the phone with the mobile app and the web server are on the same network. Or
   • Expose the web server over the internet via ngrok.

Test

1. As admin, enable "Mobile services": Site administration ► Mobile app ► Mobile settings
2. Create a new course configured to use "Separated groups" forced
3. Create two groups withing the course with the following names: g1 and g2
4. Enrol 4 users as students in the course, u1, u2, u3 and u4
5. Enrol u1 and u2 into group g1.
6. Enrol u3 and u4 into group g2
7. Enrol another user as editing teacher in the course (do not assign any group to this user)
8. Create a new assignment activity with its default configuration
9. Now, with the teacher user, access to the assignment activity via the Mobile app
10. Confirm that:
    • When selecting "All users" you see a 4 at the right of the participants row
    • When selecting g1 or g2 you only see 2 participants in the same row