Move organization_users to gitlab_main_cell

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/140343



Merged-by: Dylan Griffith <dyl.griffith@gmail.com>
Approved-by: Dylan Griffith <dyl.griffith@gmail.com>
Reviewed-by: Doug Stull <dstull@gitlab.com>
Reviewed-by: Abdul Wadood <awadood@gitlab.com>
Co-authored-by: Doug Stull <dstull@gitlab.com>