Render blame info in blob viewer

What does this MR do and why?

Renders blame info in the blob viewer behind a feature flag (scoped to JSON files).

Screenshots or screen recordings

How to set up and validate locally

1. Enable the graphql_git_blame, blob_blame_info and highlight_js_worker feature flags
2. Open a .json file via the repository files browser
3. Click the Blame button in the blob header
4. The blame info should be rendered

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 #425267 (closed)