ci: upload Playwright tests' results even in PR builds

We do that in all other workflows that run the Playwright tests, and it
is very helpful when diagnosing issues (especially the screenshots that
are stored on failure).

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

.github/workflows/ci.yml

@@ -82,4 +82,9 @@ jobs:
     - name: Run Playwright tests
       env:
         PLAYWRIGHT_TEST_URL: http://localhost:5000/
-      run: npx playwright test --project=chrome
+      run: npx playwright test --project=chrome
+    - uses: actions/upload-artifact@v4
+      if: always()
+      with:
+        name: playwright-report
+        path: playwright-report/