Resolve "Update Admin link to match context"

What does this MR do and why?

Resolves #406274 (closed), renaming the "Admin" link to "Admin Area".

Screenshots or screen recordings

Before	After

How to set up and validate locally

• Feature.enabe(:super_sidebar_nav, User.first) and toggle the New Navigation on in your user dropdown.
• Open the context switcher.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.