Remove group_ci_cd_analytics_page

What does this MR do and why?

This has been enabled by default for several milestones, and is no longer needed. Time to release the feature!

Screenshots or screen recordings

No change

How to set up and validate locally

See Analytics > CI/CD in a group's sidebar

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.

For #292601 (closed)