fix(helm): Support exisiting ServiceAccount - #482

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: mig4/setup-bats@af9a00deb21b5d795cabfeaa8d9060410377686d. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/