Add IaC scanning to Security Configuration page

What does this MR do and why?

This adds the ability to configure IaC Scanning from the Security Configuration page.

Screenshots or screen recordings

Before	After

configure_iac_scanning_720p

How to set up and validate locally

1. Enable the configure_iac_scanning_via_mr feature flag.

   Feature.enable(:configure_iac_scanning_via_mr)

2. Visit a project's Security Configuration page at http://127.0.0.1:3000/groups/flightjs/-/security/configuration
3. Click the Configure via Merge Request button in the Infrastructure as Code (IaC) Scanning section.

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 #343851 (closed)