Resolve "Add risk_score field to vulnerability ES index"

What does this MR do and why?

This MR adds the vulnerability risk score to the vulnerability ES index

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #570783 (closed)