Studio search (Meilisearch) does not include courses for authz-only users

Description

Users who have only an authz role assignment (e.g., course_editor or course_auditor) without a corresponding legacy CourseStaffRole or CourseInstructorRole are invisible to the Meilisearch search access filter. This means course content does not appear in:

• The global Studio search modal (Cmd+K / magnifying glass icon)
• The "Review Content Updates" tab on the Library Updates page (/course/{id}/libraries)

Root Cause

get_access_ids_for_request builds the Meilisearch tenant token filter using only legacy CourseStaffRole/CourseInstructorRole assignments:

course_clause = models.Q(context_key__in=[
    role.course_id
    for role in course_roles
    if role.role in [CourseInstructorRole.ROLE, CourseStaffRole.ROLE]
])

Users with authz-only roles do not have entries in the legacy CourseAccessRole table, so their courses are excluded from the access_id filter embedded in the JWT tenant token. Meilisearch enforces this filter server-side, returning zero results for any course not in the list.

Expected Behavior

When AUTHZ_COURSE_AUTHORING_FLAG is enabled, get_access_ids_for_request should also include courses where the user has an authz role assignment (any course-scoped role), so that search results are visible to editors and auditors.

Affected Pages

• Global Studio search modal (search icon in header / Cmd+K)
• Library Updates page → "Review Content Updates" tab (uses Meilisearch to look up component details)

Context

Originally reported in https://github.com/openedx/openedx-authz/issues/398#issuecomment-5369174404 during testing of the view_library_updates enforcement PR.

This is a broader issue than library updates — it affects all Meilisearch-powered features for any authz-only user who lacks an org-level role.

Suggested Fix

In openedx/core/djangoapps/content/search/models.py, update get_access_ids_for_request to query authz role assignments when the feature flag is enabled and include those course keys in the access_ids list.