Pass icons.svg as an artifact after the frontend build

What does this MR do and why?

One more fix for !49 (merged).

Files we create (or move) with Vite need to be passed as artifacts from the FE build to the Hugo build.

Merge request 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 merge request.