Shim $PropertyType in react-native for now (#50271)

Summary:
Pull Request resolved: #50271

In the next version of Flow, support for `$PropertyType` will be removed in favor of indexed access types. The final 2 usages in react-native is in `ReactNativeTypes`, which is synced from upstream react. Sync of facebook/react#32733 is currently blocked by test failures, so I will add the temporary shim to unblock releases.

Changelog: [Internal]

Reviewed By: panagosg7

Differential Revision: D71849353

fbshipit-source-id: d4787fe17ae52aa50d54f9fb7fb8b14c149aa1e6

Author: SamChou19815

packages/react-native/flow/global.js

@@ -86,3 +86,5 @@ declare var global: {
   // Undeclared properties are implicitly `any`.
   [string | symbol]: any,
 };
+
+type $PropertyType<T, K> = T[K];