Merge branch '441294-cleanup-free-trial-registration-experiment' into 'master'

Clean up successful free_trial_registration_redesign experiment

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/145235



Merged-by: Aboobacker MK <akarakath@gitlab.com>
Approved-by: Dmytro Biryukov <dbiryukov@gitlab.com>
Approved-by: Kos Palchyk <kpalchyk@gitlab.com>
Approved-by: Aboobacker MK <akarakath@gitlab.com>
Approved-by: Aaron Huntsman <ahuntsman@gitlab.com>
Approved-by: Ezekiel Kigbo <3397881-ekigbo@users.noreply.gitlab.com>
Reviewed-by: Ezekiel Kigbo <3397881-ekigbo@users.noreply.gitlab.com>
Co-authored-by: Ross Byrne <robyrne@gitlab.com>