Fix asynchronous access to KeyboardAvoidingEvent event in onLayout handler (#47798)

Summary:
The `onLayout` handler of the `KeyboardAvoidingView` view is async due to the `await AccessibilityInfo.prefersCrossFadeTransitions` in `_relativeKeyboardHeight`.

A connected `onLayout` handler will be unable to access the event. Call `persist()` on the event so that it can be accessed asynchronously.

## Changelog:

[GENERAL] [FIXED] - Accessing KeyboardAvoidingEvent event in onLayout handler

Pull Request resolved: https://github.com/facebook/react-native/pull/47798

Test Plan:
The following should not produce an error:
```
import * as React from 'react';
import {
  KeyboardAvoidingView,
  SafeAreaView,
  TextInput
} from 'react-native';

export default function() {
  return (
    <SafeAreaView>
      <KeyboardAvoidingView onLayout={(event) => console.log(event)} behavior="padding">
        <TextInput />
      </KeyboardAvoidingView>
    </SafeAreaView>
  );
}
```

Reviewed By: cipolleschi

Differential Revision: D66306085

Pulled By: dmytrorykun

fbshipit-source-id: 9ccf00db79947670ddc7de74a47cc6dc27455fc0

packages/react-native/Libraries/Components/Keyboard/KeyboardAvoidingView.js

@@ -116,6 +116,8 @@ class KeyboardAvoidingView extends React.Component<Props, State> {
   };
 
   _onLayout = async (event: ViewLayoutEvent) => {
+    event.persist();
+
     const oldFrame = this._frame;
     this._frame = event.nativeEvent.layout;
     if (!this._initialFrameHeight) {