Merge branch 'kassio/fix-pages-custom-domains-with-unique-domain-enabled' into 'master'

Fix pages custom domains redirect when unique domain is enabled

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/133330



Merged-by: Etienne Baqué <ebaque@gitlab.com>
Approved-by: Etienne Baqué <ebaque@gitlab.com>
Approved-by: Rutger Wessels <rwessels@gitlab.com>
Co-authored-by: Kassio Borges <kborges@gitlab.com>