ci: add aggregator gate

Author: LukasHirt

.github/workflows/test.yml

@@ -204,3 +204,14 @@ jobs:
           name: playwright-a11y-result-${{ strategy.job-index }}-${{ github.run_attempt }}
           path: ${{ github.workspace }}/reports/e2e/a11y-report.json
           retention-days: 7
+
+  check-tests-passed:
+    needs: [e2e-playwright]
+    runs-on: ubuntu-latest
+    if: always()
+    steps:
+      - name: Check all test jobs passed
+        run: |
+          if [[ "${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}" == "true" ]]; then
+            exit 1
+          fi