Add saved scans actions

What does this MR do and why?

This adds the actions to the Scan library in the on-demand scans index page.

Screenshots or screen recordings

Desktop	Mobile

Run scan
run_scan

Delete scan
delete_scan

How to set up and validate locally

1. Navigate to the on-demand scans index page at Security & Compliance > On-demand scans.
2. Activate the Scan library tab.
3. If you have created at least one DAST profile, it should show up here. Otherwise, create one by clicking on New DAST scan in the top right corner.

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.

Related to #341379 (closed)