Update App.js (#25905)

Summary:
use "shorthand" of `Fragment`

No need to import `Fragment` as it can be used via `<></>` vs `<Fragment><Fragment />`

## Changelog
Use shorthand for Fragment in App.js

[General] [Changed] - Use shorthand for Fragment in App.js
Pull Request resolved: #25905

Test Plan: Ci Tests should be sufficient

Differential Revision: D16666166

Pulled By: cpojer

fbshipit-source-id: 70e2c9793087bf8f5e0a5477c75f178134cbd6a1

Author: ferdicus

template/App.js

@@ -6,7 +6,7 @@
  * @flow
  */
 
-import React, {Fragment} from 'react';
+import React from 'react';
 import {
   SafeAreaView,
   StyleSheet,
@@ -26,7 +26,7 @@ import {
 
 const App = () => {
   return (
-    <Fragment>
+    <>
       <StatusBar barStyle="dark-content" />
       <SafeAreaView>
         <ScrollView
@@ -68,7 +68,7 @@ const App = () => {
           </View>
         </ScrollView>
       </SafeAreaView>
-    </Fragment>
+    </>
   );
 };