Resolve "Refactor security config spec to use mountExtended"

What does this MR do and why?

This is a follow-up MR to refactor this spec file to switch over mountExtended as this is the way to go now (instead of using extendedWrapper)

https://docs.gitlab.com/ee/development/testing_guide/frontend_testing.html#how-to-query-dom-elements

Screenshots or screen recordings

The are no UI/UX changes

How to set up and validate locally

n/a

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.

Related to #366665 (closed)