Remove all tables from Pipeline page when there is no job for the Pipeline

What does this MR do?

Remove all the tables (Pipelines/Jobs) from Pipeline when there is no job to show for the Pipeline.

Are there points in the code the reviewer needs to double check?

No.

Why was this MR needed?

To improve UX a little bit by removing a meaningless.

Screenshots (if relevant)

case (after the MR)	screenshots
Pipeline for a commit with invalid CI YAML (improved by the MR)
Pipeline for a commit with valid CI YAML (no regression by the MR)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [n/a] Documentation created/updated
• [n/a] API support added
• [n/a] Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • [n/a] Has been reviewed by Backend
  • [n/a] Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• [n/a] Internationalization required/considered
• [n/a] End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #45669 (closed)