When instance-level MR approval settings are scoped to a compliance
framework, all compliance projects will use these instance-level
settings as SSOT. MR approval settings in project settings page will be
locked out for further changes as they are now centrally managed in
Admin area.

If compliance framework is not selected at instance-level or project has
no longer has compliance label applied, the project-level MR approval
settings will refer to project-level ones as SSOT.

This change is behind a feature toggle
`project_compliance_merge_request_approval_settings`