Remove tmp index for vulnerabilities with cluster image scanning

What does this MR do and why?

This MR removes index that was used for migration (!98907 (diffs)).

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 #376132 (closed)