Remove gl-new-card styles

What does this MR do and why?

Removes gl-new-card classes (see #476988 for more details) in a few areas:

• Terms card
• Empty repo card

Screenshots or screen recordings

Before	After

How to set up and validate locally

• As an admin, enforce the acceptance of the terms: /admin/application_settings/general#js-terms-settings
• For empty state card, create an empty project

Links

• ✂️ UX Paper Cuts 17.3 → Dark mode - Design Support (#452231 - closed)
• Migration: GlCard (gl-new-card variant) to Crud (#476988)