Moves GAR menu item below the Container Registry menu item

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/143767



Merged-by: Alex Pooley <apooley@gitlab.com>
Approved-by: Kasia Misirli <kmisirli@gitlab.com>
Approved-by: Alex Pooley <apooley@gitlab.com>
Co-authored-by: Rahul Chanila <rchanila@gitlab.com>