examples: react-native-web: fix config to prefer .web.* exts (#10774)

* [examples/with-react-native-web] fix config to get .web.* extensions resolved before other

Simple issue if you have `Compo.js` & `Compo.web.js` (eg 1st for iOS/android & second for web): with current config, .web are resolved after.
My change change this situation so web extensions are resolved before the others.

I removed the `defaultLoaders` since it was not used. Tell me if that was intentional so I can add it back.

* lint-fix

Co-authored-by: Joe Haddad <timer150@gmail.com>

examples/with-react-native-web/next.config.js

@@ -1,11 +1,16 @@
 module.exports = {
-  webpack: (config, { defaultLoaders }) => {
+  webpack: config => {
     config.resolve.alias = {
       ...(config.resolve.alias || {}),
       // Transform all direct `react-native` imports to `react-native-web`
       'react-native$': 'react-native-web',
     }
-    config.resolve.extensions.push('.web.js', '.web.ts', '.web.tsx')
+    config.resolve.extensions = [
+      '.web.js',
+      '.web.ts',
+      '.web.tsx',
+      ...config.resolve.extensions,
+    ]
     return config
   },
 }