feat: Teaching Assistant role [BB-8580]

[0x29a]

Description

Adds a new Teaching Assistant course team role, which is similar to eSHE Instructor, with the only difference being that it doesn't have access to viewing and modifying grades.

Provided you set ENABLE_TEACHING_ASSISTANT_ROLE feature flag to True, as an Admin or Staff, you should see this on the Membership tab of the instructor dashboard:

Screenshot

Here is how the dashboard looks for a user with this role:

Screenshot

You can see that the Membership tab is hidden and that the Student Admin tab contains only two sections, unlike the regular Staff, from which the role in question is derived:

Screenshot

This role should be composable with any other course team roles. For example, Teaching Assistant + Admin will have the same permissions as Admin. Teaching Assistant + Discussion Admin will be able to access the membership tab, but assign only forum-related roles.

Testing instructions

1. Switch your devstack to the 0x29a/bb8580/teaching-assistant branch from the git@github.com:open-craft/edx-platform.git repo.
2. Set ENABLE_TEACHING_ASSISTANT_ROLE to True.
3. Create two users: course_staff@example.com and ta@example.com. Give the former Staff course team role using the Instructor Dashboard.
4. Since we've changed the instructor.enroll, instructor.give_student_extension, and instructor.override_grades permissions, verify that course_staff@example.com still can enroll students (Membership tab) and that all features on the Student Admin tab work for this user as before.
5. Now, give ta@example.com the Teaching Assistant role.
6. As ta@example.com, verify that you have access to the Instructor Dashboard, but not to the Membership tab.
7. Also, check that ta@example.com sees only two sections on the Student Admin tab of the dashboard.
8. Now, give ta@example.com the Staff role and verify that it has all Staff permissions (can enroll students, see the Membership tab and all Student Admin content).
9. Remove the Staff role from ta@example.com, give Discussion Admin and verify that it can assign forum moderator roles.
10. Remove the Forum Discussion role from ta@example.com, give Data Researcher and verify that it can access the Data Download tab.

Additionally, this script can be used to test that the instructor.enroll, instructor.give_student_extension, and instructor.override_grades permissions work as expected:

from django.contrib.auth import get_user_model
from openedx.core.lib.courses import get_course_by_id
from opaque_keys.edx.keys import CourseKey
from lms.djangoapps.courseware.rules import HasAccessRule, HasRolesRule

course_key = CourseKey.from_string("course-v1:Test+Test+Test")
course = get_course_by_id(course_key)
user = get_user_model().objects.get(email="ta@example.com")

assert not user.has_perm('instructor.enroll', course_key)
assert not user.has_perm('instructor.give_student_extension', course_key)
assert not user.has_perm('instructor.override_grades', course_key)

[CefBoud]

Great job on this one, @0x29a !
LGTM ✅

• I tested this: followed the testing instructions
• I read through the code
• Includes documentation (N/A)