Replace flot with Chart.js - #6753

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: gsactions/commit-message-checker@8c8c0d18ba9b1fcfed6e7385fd2bf357dfc8dccb. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/