Feat: wiki top level discussions

• Please check this box if this contribution uses AI-generated content (including content generated by GitLab Duo features) as outlined in the GitLab DCO & CLA. As a benefit of being a GitLab Community Contributor, you can request access to GitLab Duo.
• Please check this box if this contribution uses AI-generated content as outlined in the GitLab DCO & CLA

What does this MR do and why?

This PR attempts to add a comment section to the Gitlab Wiki pages. Reference Epic: &14062

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Enable feature flag wiki_comments.
2. Clone the Repo
3. Navigate to any project wiki
4. You should now be able to add notes