Remove seeding of default organization for dependency_management

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/176006



Merged-by: Matthias Käppler <mkaeppler@gitlab.com>
Approved-by: Charlie Kroon <ckroon@gitlab.com>
Approved-by: Matthias Käppler <mkaeppler@gitlab.com>
Co-authored-by: Rutger Wessels <rwessels@gitlab.com>