A teacher can set a maximum grade for a lesson activity

This test requires a lesson activity containing questions which several students have attempted.

1. Login as a teacher and view the course gradebook, taking note of the lesson grades.
2. Update the lesson activity, changing the maximum grade to half its previous value.
3. View the gradebook and check that the lesson grades are half their previous values.
4. Update the lesson activity and set the maximum grade to 0.
5. Check that the lesson activity is no longer displayed in the gradebook.