Update an existing resource access grant (change role).This is a more atomic alternative to revoking and re-granting access.
Preserves the access ID and created_at timestamp.User must have write permission on the resource.Note: For org-level permissions, use OrganizationMember roles instead.:param request_fastapi: FastAPI request object.
:param resource_type: Type of resource (“project”).
:param resource_id: Resource ID.
:param access_id: ResourceAccess ID to update.
:param update_data: Update data containing new role_id.
:param session: Database session.
:return: Updated access entry.