The `repository_access_level` attribute doesn't exist in the 8-12-stable
branch so repository access cannot be restricted using this feature.

Fortunately we use `can?(user, :download_code, ref_project)` in
lib/banzai/reference_parser/commit_parser.rb and
lib/banzai/reference_parser/commit_range_parser.rb and this permission
already exists in 8-12-stable (it only depends on the project
`visibility_access`).
Signed-off-by: Rémy Coutable <remy@rymai.me>