Always output the coverage report

I intended to do this in 647e95e,
but the `failure()` call that I remove didn't limit it to failures
— it explicitly enabled it for failing jobs, where the default is
to skip subsequent jobs after a failure. However, if we want a job
to run after both failed and successful runs, we need the
`always()` call.

.github/workflows/unittests.yaml

@@ -29,6 +29,7 @@ jobs:
       - run: npm test -- --coverageThreshold='{"global":{"branches":80,"functions":80,"lines":80,"statements":80}}'
         if: github.event_name == 'schedule'
       - uses: actions/upload-artifact@v4
+        if: always()
         with:
           name: coverage-report
           path: coverage/