Bump actions/download-artifact from 4.1.4 to 4.1.6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4.1.4 to 4.1.6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@c850b93...9c19ed7)

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

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

Author: dependabot[bot]

.github/workflows/upstream-nightly.yml

@@ -108,7 +108,7 @@ jobs:
       - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d # ratchet:actions/setup-python@v5
         with:
           python-version: "3.x"
-      - uses: actions/download-artifact@c850b930e6ba138125429b7e5c93fc707a7f8427 # ratchet:actions/download-artifact@v4
+      - uses: actions/download-artifact@9c19ed7fe5d278cd354c7dfd5d3b88589c7e2395 # ratchet:actions/download-artifact@v4
         with:
           path: /tmp/workspace/logs
       - name: install requirements