Avoid error when creating forks and restricted levels are defined
What does this MR do?
This fixes a crash when forking a project when no restricted access levels are defined in the application settings.
The crash wash introduced in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16050
Does this MR meet the acceptance criteria?
- Changelog entry added, if necessary
- Documentation created/updated
- API support added
- Tests added for this feature/bug
- Has been reviewed by UX
- Has been reviewed by Frontend
- Has been reviewed by Backend
- Has been reviewed by Database
- Conform by the merge request performance guides
- Conform by the style guides
- Squashed related commits together
- Internationalization required/considered
End-to-end tests pass (
package-qamanual pipeline job)