Bump actions/download-artifact from 4 to 6 (#11229)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v4...v6)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build_all.yml

@@ -90,7 +90,7 @@ jobs:
       - name: Apt-Install Dependencies
         uses: ./.github/actions/apt-install-deps
       - name: Restore Test Artifact
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
         with:
           name: ${{ github.sha }}-tests
       - uses: lukka/get-cmake@latest