GitLab Version - Badge CTA

What does this MR do and why?

Closes #368421 (closed)

This change adds a CTA to the Version Check badge. This CTA is a link to https://docs.gitlab.com/ee/update/. This CTA is going to be used to start tracking basic upgrade analytics via #369442 (closed)

The version check badge exists on the following UIs:

1. Help Page (/help)
2. Admin Dashboard (/admin)
3. Help Dropdown (? icon in the top nav)

For the nav bar help dropdown this change also makes the entire <li> a clickable link to align with the other items in that dropdown.

Screenshots or screen recordings

	Before	After
Help Page (Badge Focused)
Admin Dashboard (Badge Focused)
Help Dropdown (Badge Focused)

How to set up and validate locally

Important

1. Ensure Gitlab::CurrentSettings.version_check_enabled is set to true (it defaults to true)
2. Version Check uses ReactiveCache so the first time you navigate to a place where the badge should be, it may not be in the cache and required a single reload.

Testing Instructions

1. Repeat these steps for the following views
   • /help
   • /admin
   • Help Dropdown (? in top nav)
2. Find the Version Check badge
   • /help => At top of page
   • /admin => In the components card
   • Help Dropdown => First list item
3. Ensure the badge links to https://docs.gitlab.com/ee/update/
4. For the Help Dropdown, ensure the entire list item also links to https://docs.gitlab.com/ee/update/.

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.

cc/ @dorrino @sunjungp
Related to #368421 (closed)