Update: XIAO_nRF54LM20A-Sense_Getting_Started.md - revise PlatformIO update commands - #5425

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/github-script@v7. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/