Merge branch 'morefice/fix-validate-partitioned-fk' into 'master'

Check FK existence in validate_partitioned_foreign_key

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144431



Merged-by: Marius Bobin <mbobin@gitlab.com>
Approved-by: Panos Kanellidis <pkanellidis@gitlab.com>
Approved-by: Marius Bobin <mbobin@gitlab.com>
Reviewed-by: Max Orefice <morefice@gitlab.com>
Reviewed-by: Panos Kanellidis <pkanellidis@gitlab.com>
Co-authored-by: Maxime Orefice <morefice@gitlab.com>