[Feature flag] Enable create_vulnerabilities_via_api by default

What does this MR do and why?

This MR enables create_vulnerabilities_via_api globally

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 #338694 (closed)