Add application and group setting UI for built_in_project_templates_enabled
To support https://gitlab.com/groups/gitlab-org/-/work_items/21356+, we should add UI elements to toggle both the application and group setting.
Display cascading settings on the frontend documentation: https://docs.gitlab.com/development/cascading_settings/#display-cascading-settings-on-the-frontend
Example MRs:
- https://gitlab.com/gitlab-org/gitlab/-/merge_requests/92218
- https://gitlab.com/gitlab-org/gitlab/-/merge_requests/201399
issue