build: install cudnn-frontend from feat/1.29.0-megatron in fw_final image - #6427

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11d5960a326750d5838078e36cf38b85af677262. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Summary report available at: https://github.com/NVIDIA-NeMo/Megatron-Bridge/actions/runs/38435467445#summary-115433426958