Merge branch 'jh/migrate_subscription_put' into 'master'

Move subscription update API to new module

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/156598



Merged-by: Thong Kuah <tkuah@gitlab.com>
Approved-by: Thong Kuah <tkuah@gitlab.com>
Reviewed-by: Bishwa Hang Rai <bhrai@gitlab.com>
Co-authored-by: Josianne Hyson <jhyson@gitlab.com>