feat[Fabric/Paper]: support isChildPublicInstance api method (#27783)

Adds `isChildPublicInstance` method to both renderers (Fabric and
Paper), which will receive 2 public instances and return if first
argument is an ancestor of the second, based on fibers.

This will be used as a fallback when DOM node APIs are not available:
for Paper renderer or for Fabric without DOM node APIs.

How it is going to be used: to determine which `AppContainer` component
in RN is responsible for highlighting an inspected element on the
screen.

scripts/flow/react-native-host-hooks.js

@@ -159,6 +159,9 @@ declare module 'react-native/Libraries/ReactPrivate/ReactNativePrivateInterface'
   declare export function createPublicTextInstance(
     internalInstanceHandle: mixed,
   ): PublicTextInstance;
+  declare export function getInternalInstanceHandleFromPublicInstance(
+    publicInstance: PublicInstance,
+  ): ?Object;
 }
 
 declare module 'react-native/Libraries/ReactPrivate/ReactNativePrivateInitializeCore' {