fix(ocpp-wamp): fix the client races behind the flaky ocpp-wamp tests - #147

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5, actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9, gradle/actions/setup-gradle@748248ddd2a24f49513d8f472f81c3a07d4d50e1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/