ESM error running tests on Node.js v25

[JoshMock]

Recent PRs that run the client tests are failing on Node.js v25 with the following error:

file:///home/runner/work/elastic-transport-js/elastic-transport-js/client/node_modules/yargs/yargs:3
const {applyExtends, cjsPlatformShim, Parser, Yargs, processArgv} = require('./build/index.cjs')
                                                                    ^
ReferenceError: require is not defined in ES module scope, you can use import instead
    at file:///home/runner/work/elastic-transport-js/elastic-transport-js/client/node_modules/yargs/yargs:3:69
    at ModuleJobSync.runSync (node:internal/modules/esm/module_job:534:37)
    at ModuleLoader.importSyncForRequire (node:internal/modules/esm/loader:366:47)
    at loadESMFromCJS (node:internal/modules/cjs/loader:1628:24)
    at Module._compile (node:internal/modules/cjs/loader:1793:5)
    at Object..js (node:internal/modules/cjs/loader:1951:10)
    at Module.load (node:internal/modules/cjs/loader:1532:32)
    at Module._load (node:internal/modules/cjs/loader:1334:12)
    at wrapModuleLoad (node:internal/modules/cjs/loader:255:19)
    at Module.require (node:internal/modules/cjs/loader:1555:12)

Presumably an ESM-related issue with a dev dependency that needs to get cleaned up.