Add pre-scan verification sidebar on Scan Library page

What does this MR do and why?

Describe in detail what your merge request does and why.

This MR resolves #376705 (closed)

This MR adds pre-scan verification flow to a list of on-demand scans.

This should work according to this prototype

backend is still in progress, so this MR covers only frontend part for now

Task/issue	MR
Create feature flag / lay groundwork - #376687 (closed)	!100322 (merged)
Create pre-scan verification component - #376690 (closed)	!100593 (merged)
Add drawer for pre-scan verification - #376708 (closed)	!100694 (merged)
Add status summary component to a drawer - #377509 (closed)	!100937 (merged)
Add stepped list for pre-scan verification flow - #377854 (closed)	!101257 (merged)
Add alert message to a sidebar - #378272 (closed)	!102389 (merged)
Add option on Scan Library page - #376705 (closed)	!102290 (merged)
Add Pre-scan verification column to Scan Library tab - #376692	TBD

Screenshots or screen recordings

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after
pre-scan

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Enable flag by enabling rails console in terminal

   Feature.enable(:dast_pre_scan_verification)

2. Edit the code to see different states (instructions here)
3. Go to BASE_URL/PROJECT_ID/-/on_demand_scans
4. Select scan library tab (create new on-demand scan if there are none)
5. Select dotted menu on the ride side and click Verify configuration

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 #376705 (closed)