fix: set correct default when using react-scripts plugin (#20141)

Author: lmiller1990

npm/react/examples/react-scripts/cypress/plugins/index.js

@@ -8,7 +8,7 @@ const devServer = require('@cypress/react/plugins/react-scripts')
  * @type {Cypress.PluginConfig}
  */
 module.exports = (on, config) => {
-  devServer(on, config)
+  devServer(on, config, {})
 
   // IMPORTANT to return the config object
   // with the any changed environment variables

npm/react/plugins/react-scripts/findReactScriptsWebpackConfig.js

@@ -7,9 +7,11 @@ const { getTranspileFolders } = require('../utils/get-transpile-folders')
 const { addFolderToBabelLoaderTranspileInPlace } = require('../utils/babel-helpers')
 const { reactScriptsFiveModifications, isReactScripts5 } = require('../../dist/react-scripts/reactScriptsFive')
 
-module.exports = function findReactScriptsWebpackConfig (config, {
-  webpackConfigPath,
-} = { webpackConfigPath: 'react-scripts/config/webpack.config' }) {
+module.exports = function findReactScriptsWebpackConfig (config, devServerOptions) {
+  const webpackConfigPath = (devServerOptions && devServerOptions.webpackConfigPath)
+    ? devServerOptions.webpackConfigPath
+    : 'react-scripts/config/webpack.config'
+
   // this is required because
   // 1) we use our own HMR and we don't need react-refresh transpiling overhead
   // 2) it doesn't work with process.env=test @see https://github.com/cypress-io/cypress-realworld-app/pull/832