Wrong safe area in presence of absolute-positioned view

# Bug report
## Summary

As you can see from the screenshot, the safe area is computed wrongly when a view with `position: absolute` is placed near the view pager.

## Environment info
`react-native info` output:
```bash
System:
OS: macOS 10.15.4
CPU: (4) x64 Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
Memory: 21.57 MB / 8.00 GB
Shell: 5.7.1 - /bin/zsh
Binaries:
Node: 12.14.1 - ~/.nvm/versions/node/v12.14.1/bin/node
Yarn: 1.22.4 - /usr/local/bin/yarn
npm: 6.13.7 - ~/.nvm/versions/node/v12.14.1/bin/npm
Watchman: 4.9.0 - /usr/local/bin/watchman
Managers:
CocoaPods: 1.8.4 - /usr/local/bin/pod
SDKs:
iOS SDK:
Platforms: iOS 13.5, DriverKit 19.0, macOS 10.15, tvOS 13.4, watchOS 6.2
Android SDK: Not Found
IDEs:
Android Studio: 4.0 AI-193.6911.18.40.6514223
Xcode: 11.5/11E608c - /usr/bin/xcodebuild
Languages:
Java: 9.0.4 - /usr/bin/javac
Python: 3.7.2 - /Users/federico/miniconda3/bin/python
npmPackages:
@react-native-community/cli: Not Found
react: 16.9.0 => 16.9.0
react-native: 0.62.2 => 0.62.2
npmGlobalPackages:
*react-native*: Not Found
```

Library version: "^4.0.0",

## Steps to reproduce
```js
const ViewPagerScreen = (props) => {

const pages = [



Title text



];

return (
<>

{pages}


// if you remove this problematic footer view, all works as expected




{}} />


{}} />

);
}

const styles = StyleSheet.create({
footer: {
flexDirection: "row",
marginBottom: 20,
backgroundColor: 'yellow'
},
footerSubContLeft: {
flex: 1,
alignItems: "flex-start",
},
footerSubContRight: {
flex: 1,
alignItems: "flex-end",
}
});
```

Describe what you expected to happen:

The text view should be inside the SafeArea. If I remove the yellow view (footer), this is respected.

Inizia riproducendo su iOS l'esempio fornito con ViewPager, SafeAreaView e un footer posizionato in modo assoluto, utilizzando le versioni indicate di React Native e delle librerie. Esamina l'interazione tra ViewPager e SafeAreaView; il lavoro è completato quando il testo rimane all'interno dell'area sicura quando è presente la vista del footer, in corrispondenza dello screenshot previsto.

Scritto dal modello di indicizzazione a partire dal testo della issue.