Merge branch '444643_add_not_null_constraints' into 'master'

Remove invalid remote mirror records without "project_id"

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/146640



Merged-by: Tiger Watson <twatson@gitlab.com>
Approved-by: Vitali Tatarintev <vtatarintev@gitlab.com>
Approved-by: Tiger Watson <twatson@gitlab.com>
Co-authored-by: Vasilii Iakliushin <viakliushin@gitlab.com>