Use confirm variant for new wiki template

What does this MR do and why?

• Remove icon
• Use confirm variant

Screenshots or screen recordings

Before	After

How to set up and validate locally

Go to wiki templates page (ie http://127.0.0.1:3000/gitlab-org/gitlab-test/-/wikis/templates)

Links

• ✂️ UX Paper Cuts 17.1 → Wiki (#452225)