If enabled, a teacher can select a course theme

This test requires course and user themes to be enabled by an admin in Administration > Appearance > Themes > Theme settings.

1. Login as a teacher, edit profile and select a preferred theme which is different from the site theme.
2. Check that the selected theme overrides the site theme.
3. In the course settings, select a different theme again for the course.
4. Check that the course theme overrides the site and user themes.