Cleanup babel config (#5414)

babel.config.json

@@ -0,0 +1,10 @@
+{
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "modules": "commonjs"
+      }
+    ]
+  ]
+}

package.json

@@ -76,12 +76,6 @@
     "@babel/cli": "7.25.6",
     "@babel/core": "7.25.2",
     "@babel/eslint-parser": "7.25.1",
-    "@babel/plugin-proposal-class-properties": "7.18.6",
-    "@babel/plugin-proposal-decorators": "7.24.7",
-    "@babel/plugin-proposal-export-namespace-from": "7.18.9",
-    "@babel/plugin-proposal-function-sent": "7.24.7",
-    "@babel/plugin-proposal-numeric-separator": "7.18.6",
-    "@babel/plugin-proposal-throw-expressions": "7.24.7",
     "@babel/preset-env": "7.25.4",
     "@babel/register": "7.24.6",
     "async": "3.2.6",

webpack.config.js

@@ -24,7 +24,7 @@ module.exports = {
     rules: [
       {
         use: 'babel-loader',
-        // babel options are in .babelrc
+        // babel options are in babel.config.json
         exclude: /(node_modules|bower_components)/,
         test: /\.js$/,
       },

webpack.l10n.config.babel.js

@@ -5,7 +5,7 @@ const webpack = require('webpack');
 
 const webpackConfig = require('./webpack.config');
 
-const babelrc = fs.readFileSync('./.babelrc');
+const babelrc = fs.readFileSync('./babel.config.json');
 const babelrcObject = JSON.parse(babelrc);
 const babelPlugins = babelrcObject.plugins || [];