chore: bump actions/download-artifact from 4 to 8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v4...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/hotpath-comment.yml

@@ -19,7 +19,7 @@ jobs:
 
       - uses: actions-rust-lang/setup-rust-toolchain@v1
 
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v8
         with:
           name: profile-metrics
           path: /tmp/metrics/