Remove pipeline banner

What does this MR do and why?

• Remove pipeline banner
• Fix illustration size

Screenshots or screen recordings

Before	After

How to set up and validate locally

• Go to /gitlab-org/gitlab-test/-/pipeline_schedules
• See empty state with no banner
• Create a schedule with any fake info
• See the table with no banner

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.

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UX Paper Cuts 16.4 → Pipelines and Jobs (#408231 - closed), UX Paper Cuts 16.5 → Cleanup (#424403 - closed)