Added sharedAction example to Share API (#30333)

Summary:
* Added an example for `sharedAction` and `dismissedAction` in Share API examples

**Motivation** - Missing example for `sharedAction` in examples

## Changelog

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[General] [Added] - Added an example in ShareExample.js

Pull Request resolved: https://github.com/facebook/react-native/pull/30333

Test Plan:
* Tested on Android

![sharedAction](https://user-images.githubusercontent.com/26821140/98447958-ed758600-214e-11eb-8a50-67ad5dcebea5.png)

Reviewed By: cpojer

Differential Revision: D25246375

Pulled By: rickhanlonii

fbshipit-source-id: f0d25a04c77ba02c9bea07aceccbfb65b2aa67e9

Libraries/Components/ScrollView/ScrollViewStickyHeader.js

@@ -177,7 +177,7 @@ class ScrollViewStickyHeader extends React.Component<Props, State> {
     // Fabric Detection
     // eslint-disable-next-line dot-notation
     const isFabric = !!(
-      this._ref && this._ref['_internalInstanceHandle']?.stateNode?.canonical
+      this._ref && this._ref._internalInstanceHandle?.stateNode?.canonical
     );
 
     // Initially and in the case of updated props or layout, we

packages/rn-tester/js/examples/Share/ShareExample.js

@@ -76,6 +76,46 @@ const ShareMessageWithTitle = () => {
   );
 };
 
+const SharedAction = () => {
+  const [shared, setShared] = React.useState();
+
+  const sharedAction = async () => {
+    try {
+      const result = await Share.share(
+        {
+          title: 'Create native apps',
+          message: ('React Native combines the best parts of native development with React, a best-in-class JavaScript library for building user interfaces.': string),
+          url: 'https://reactnative.dev/',
+        },
+        {
+          subject: 'MUST READ: Create native apps with React Native',
+          dialogTitle: 'Share React Native Home Page',
+          tintColor: 'blue',
+        },
+      );
+      if (result.action === Share.sharedAction) {
+        setShared(result.action);
+      } else if (result.action === Share.dismissedAction) {
+        //iOS only, if dialog was dismissed
+        setShared(null);
+      }
+    } catch (e) {
+      console.error(e);
+    }
+  };
+  return (
+    <View style={styles.container}>
+      <Text>action: {shared ? shared : 'null'}</Text>
+      <Text style={styles.title}>Create native apps</Text>
+      <Text>
+        React Native combines the best parts of native development with React, a
+        best-in-class JavaScript library for building user interfaces.
+      </Text>
+      <Button title="SHARE" onPress={sharedAction} />
+    </View>
+  );
+};
+
 const styles = StyleSheet.create({
   container: {
     flex: 1,
@@ -104,4 +144,10 @@ exports.examples = [
       return <ShareMessageWithTitle />;
     },
   },
+  {
+    title: 'sharedAction: If the content was successfully shared',
+    render(): React.Node {
+      return <SharedAction />;
+    },
+  },
 ];