Resolve "[Meta] Create Uniquely 'GitLab' Icons"

What does this MR do?

Update icon style information to reflect the new system.

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed?

The 10 release post details our updated icons and points to this area, it needed a quick update to reflect the new information.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #32894 (closed)