message: hub/plugin-loader: Simplify duplicate plugin error handling
  The code after the condition block was only executed for the `this.environment !== 'test'` case, so we should drop out early with the thrown exception and run the rest of the code outside of the condition
diff: @@ -135,14 +135,16 @@ class PluginLoader {
  let dupeModule = Object.values(seen).find(i => i.id === json.name);
  if (dupeModule) {
  let msg = action => `The plugin module name '${json.name}' has already been loaded from the module path ${dupeModule.attributes.rawDir}, ${action} load of module at path ${dir}.`;
  - if (this.environment !== 'test') {
  - log.warn(msg('skipping'));
  - } else {
  + if (this.environment === 'test') {
  throw new Error(msg('conflict with'));
  }
  +
  + log.warn(msg('skipping'));
  +
  if (get(dupeModule, 'attributes.includedFrom')) {
  dupeModule.attributes.includedFrom.push(breadcrumbs);
  }
  +
  return;
  }
  