message: auth: remove duplicated use of defaultAuthProviderFactories
diff: import {
  createGoogleProvider,
  createRouter,
  - defaultAuthProviderFactories,
  } from '@backstage/plugin-auth-backend';
  import { Router } from 'express';
  import { PluginEnvironment } from '../types';
  @@ -34,7 +33,6 @@ export default async function createPlugin({
  database,
  discovery,
  providerFactories: {
  - ...defaultAuthProviderFactories,
  google: createGoogleProvider({
  signIn: {
  // resolver: 'email',
  