Export NewAppScreen from the root

Summary:
New react native projects from react-native-communit/template use components from the `NewAppScreen` which is currently not root exported:

```
import {
  Colors,
  DebugInstructions,
  Header,
  LearnMoreLinks,
  ReloadInstructions,
} from 'react-native/Libraries/NewAppScreen';
```

This diff adds re-export of the NewAppScreen as a namespace to state the origin of imported components clearly.

Changelog:
[Internal]

Differential Revision: D73242541

Author: coado

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -9082,6 +9082,7 @@ export type {
   VirtualizedSectionListProps,
 } from \\"./Libraries/Lists/VirtualizedSectionList\\";
 export { default as VirtualizedSectionList } from \\"./Libraries/Lists/VirtualizedSectionList\\";
+export * as NewAppScreen from \\"./Libraries/NewAppScreen\\";
 export { default as AccessibilityInfo } from \\"./Libraries/Components/AccessibilityInfo/AccessibilityInfo\\";
 export type {
   ActionSheetIOSOptions,

packages/react-native/index.js

@@ -132,6 +132,9 @@ module.exports = {
   get VirtualizedSectionList() {
     return require('./Libraries/Lists/VirtualizedSectionList').default;
   },
+  get NewAppScreen() {
+    return require('./Libraries/NewAppScreen');
+  },
   // #endregion
   // #region APIs
   get AccessibilityInfo() {

packages/react-native/index.js.flow

@@ -192,6 +192,8 @@ export type {
 } from './Libraries/Lists/VirtualizedSectionList';
 export {default as VirtualizedSectionList} from './Libraries/Lists/VirtualizedSectionList';
 
+export * as NewAppScreen from './Libraries/NewAppScreen';
+
 // #endregion
 // #region APIs