* chore: update API endpoints to support default JWT auth
The default DRF Auth classes were recently updated to allow for both JWT and Session auth by default. Any endpoint that overrides the AUTHENTICATION_CLASSES but has just session, just JWT or just both of those should be updated to remove the override.
Details in https://github.com/openedx/edx-platform/issues/33662
[MICROBA-1510]
- Add support for updating an instructor task schedule date via REST API
- Add support for updating the contents of a scheduled course email via REST API
[MICROBA-1510]
* update InstructorTaskSchedule model delete behavior from CASCADE to DO_NOTHING.
* add utility function supporting cancellation of scheduled tasks to the instructor_task app
* add utility function to determine if a user has staff or instructor level access to a course to the student app
* adds a REST API for supporting retrieval and cancellation of scheduled bulk email tasks
* add unit tests for new functionality in the student app
* add unit tests for the new functionality in the bulk_email app
* remove use of CourseEmail object directly in another related test file
* add unit tests for the new REST API views.
