Removes database migrations up to 16-2-stable-ee

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149003



Merged-by: Jon Jenkins <jjenkins@gitlab.com>
Approved-by: Jon Jenkins <jjenkins@gitlab.com>
Approved-by: Matt Kasa <mkasa@gitlab.com>
Approved-by: Nao Hashizume <nhashizume@gitlab.com>
Co-authored-by: Leonardo Rosa <ldarosa@gitlab.com>