fix(data): add missing DataStore polyfill to React Native 'Getting Started' / 'Integrate your app' page (aws-amplify#5309) (aws-amplify#5310)

Author: david-mcafee

src/fragments/start/getting-started/reactnative/integrate.mdx

@@ -1,5 +1,9 @@
 In this section you’ll integrate Amplify DataStore with your app, and learn to use the generated data model to create, update, query, and delete Todo items by building an app. You can find the source code of the final Todo App [on our GitHub repository](https://github.com/chintannp/amplified_todo_rn).
 
+import polyfillCallout from '/src/fragments/lib/datastore/react-native/getting-started/polyfills.mdx';
+
+<Fragments fragments={{ 'react-native': polyfillCallout }} />
+
 ## Boilerplate UI
 First, you will create some files and place the boilerplate UI code in it.