Duo Health Check - Child components

What does this MR do and why?

Part 2 / 2 for #480519 (closed)

This change refactors the GitLab Duo Health Check List into having child components for categories and probes. This helps isolate the tests and make the code generally more readable.

Screenshots or screen recordings

Before	After (No Change)

How to set up and validate locally

1. Setup GitLab Duo on your GDK by following these docs: https://docs.gitlab.com/ee/development/ai_features/index.html#option-b-run-gdk-in-self-managed-mode-and-enable-ai-features-for-the-instance
2. Navigate to admin/code_suggestions
3. Ensure no visual changes