Use simple copy for scratch-component.html

Using the html webpack copy plugin meant that our scratch-component.html
page ended up with script tags loading both web-component.js and
PyodideWorker.js (corresponding to `entry` keys in webpack.config.js).
We don't need those in scratch-component.html and we want to rule out
whether their presence is causing the errors we're currently seeing when
deploying editor-ui using github actions.

webpack.config.js

@@ -140,14 +140,10 @@ module.exports = {
       template: "src/web-component.html",
       filename: "web-component.html",
     }),
-    new HtmlWebpackPlugin({
-      inject: "body",
-      template: "src/scratch-component.html",
-      filename: "scratch-component.html",
-    }),
     new CopyWebpackPlugin({
       patterns: [
         { from: "public", to: "" },
+        { from: "src/scratch-component.html", to: "scratch-component.html" },
         { from: "scratch/dist/main.js", to: "scratch.js" },
         // { from: "scratch/node_modules/scratch-gui/dist/static/blocks-media/default/*.svg", to: "static/blocks-media/default/[name][ext]" },
         // { from: "scratch/node_modules/scratch-gui/dist/static/blocks-media/high-contrast/*.svg", to: "static/blocks-media/high-contrast/[name][ext]" },