Make roles and permissions visible for Premium Licenses

What does this MR do and why?

Make roles and permissions page visible to Premium licensed customers. Only default roles will be shown, as custom roles are only available for Ultimate licensed groups or instances.

Issue: #475123 (closed)

Screenshots or screen recordings

	Ultimate License	Premium License
GitLab.com group owner
Self-Managed admin

How to set up and validate locally

For Self-Managed

1. Activate a Premium License for the instance
2. Visit http://gdk.test:3000/admin/application_settings/roles_and_permissions
3. Verify the page is accessible and the New role button is not shown

For GitLab.com

1. Simulate SaaS
2. Create a group with Premium License
3. Visit http://gdk.test:3000/groups/{{new-group}}/-/settings/roles_and_permissions
4. Verify the page is accessible and the New role button is not shown