Remove extension assets copying

webpack.config.js

@@ -111,10 +111,6 @@ module.exports = {
             from: 'node_modules/scratch-blocks/media',
             to: 'static/blocks-media'
         }]),
-        new CopyWebpackPlugin([{
-            from: 'node_modules/scratch-vm/dist/node/assets',
-            to: 'static/extension-assets'
-        }]),
         new CopyWebpackPlugin([{
             from: 'extensions/**',
             to: 'static',