Add RCA feature to failed jobs widget

What does this MR do and why?

Adds the ability to troubleshoot failed jobs via AI on an MR failed jobs widget.

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

How to set up and validate locally

1. Have duo setup https://docs.gitlab.com/ee/development/ai_features/index.html
2. Enable feature flag ci_job_failures_in_mr
3. Visit MR with failed jobs, ensure the widget displays troubleshoot button and opens duo chat with correct job id
4. Visit failed job directly and ensure troubleshoot button under job log still displays and works as expected

Related to #482497 (closed)