This PR addresses four test improvements across the Soroban contracts and NestJS backend. - #1304

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683, actions/dependency-review-action@a6993e2c61fd5dc440b409aa1d6904921c5e1894. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/