Fix error when dynamic importing js files which imports raw files

[marcioj]

For example given the following files:

cat.js

import cat from './cat.jpg';

export default function renderCat() {
  // renders <img src={cat} > somehow
}

app.js

import('./cat.js').then(modules => modules.default())

Throws TypeError: bundleLoaders[type] is not a function because bundleLoaders has just css and js handlers.

Note this is different from dynamic importing the jpg file directly, which I believe is not supported in the moment. In this case we are lazy loading a js file but it depends on a raw asset.