Add additional mechanisms to prevent deletion of overage_terms_acceptances records
The following discussion from !13864 should be addressed:
- [ ] @paulobarros started a [discussion](https://gitlab.com/gitlab-org/customers-gitlab-com/-/merge_requests/13864#note_2851220322): (+1 comment)
> This won't protect against raw `DELETE` queries, for example. Also calling `delete_all` could bypass this, I think.
>
> Maybe it's better to enforce this on the database-level with a trigger? Or at least prevent the most common ways to bypass at the Rails level? :thinking:
>
> Happy to involve a database maintainer here.
issue