Bump actions/download-artifact from 6 to 7

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/tests.yaml

@@ -87,7 +87,7 @@ jobs:
 
       # Download all coverage artifacts from matrix jobs
       - name: Download coverage data
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           pattern: coverage-data-*
           merge-multiple: true