To support https://gitlab.com/groups/gitlab-org/-/work_items/21356+, the setting should be configurable from the GraphQL API. Instance level settings are not exposed in GraphQL, so this only needs to cover the group setting. This should be behind the `use_built_in_project_templates_enabled` feature flag, and added as an `experiment`. An example MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/146430