github-actions: bump actions/download-artifact from 4.1.4 to 4.1.8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4.1.4 to 4.1.8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4.1.4...fa0a91b)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>