Course Auditor receives 403 error when navigating to course units

[BryanttV]

Description

Currently, a user assigned the "Course Auditor" role can successfully access and view the course outline. However, when the user attempts to enter or navigate to a specific unit, the backend returns a 403 Forbidden error.

Expected behavior

Based on the Figma designs and role definitions, a Course Auditor should have read-only access to navigate through the course content, including viewing individual units, without encountering permission errors.

Actual behavior

The backend blocks access to the unit level with a 403 error, despite the user having visibility of the course outline.

Steps to reproduce

1. Log in with an account that has the Course Auditor role for a specific course.
2. Navigate to the course outline (this works as expected).
3. Click on any unit to view its content.
4. Observe the backend returning a 403 Forbidden error and preventing navigation.

Additional Context

• This seems to be an authorization (AuthZ) gap where the "Course Auditor" role has not been granted the necessary read permissions for the underlying XBlocks or LMS unit views.
• Needs investigation into the permission classes or block access checks gating the unit views.