Resolve "Remove the checkbox for starting a new pipeline in Auto DevOps settings"

What does this MR do?

Removes Auto DevOps checkboxes to start a new pipeline in the Settings page.

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

Why was this MR needed?

We don't need the checkboxes here.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

Closes #40761 (closed)