fix(ci): Add sequential E2E tests workflow to improve CI stability

- Introduced a new workflow for E2E tests that runs tests sequentially to avoid race conditions caused by parallel execution.
- Reduced the number of shards from 4 to 1 per browser, ensuring all tests for each browser run sequentially.
- Updated the existing WAF integration workflow to include pull request triggers for better CI management.

.github/workflows/docker-build.yml

@@ -129,7 +129,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Log in to Docker Hub
-        if: github.event_name != 'pull_request' && steps.skip.outputs.skip_build != 'true' && env.HAS_DOCKERHUB_TOKEN == 'true'
+        if: steps.skip.outputs.skip_build != 'true' && env.HAS_DOCKERHUB_TOKEN == 'true'
         uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
         with:
           registry: docker.io