Remove failed_jobs_tab_vue feature flag

What does this MR do and why?

This removes the failed_jobs_tab_vue feature flag, enabling the feature for everyone

#360849 (closed)

Screenshots or screen recordings

No visual change for this refactor, this was more of porting a HAML feature to Vue

How to set up and validate locally

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

1. Have a project with configured runners and a failed job
2. Go to the pipeline page and click the Failed Jobs tab

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.