Fix react-native polyfill to prevent multiple polyfills

Author: WillsonHaw

.changeset/large-plums-create.md

@@ -0,0 +1,5 @@
+---
+"@plextv/react-native-lightning": patch
+---
+
+Fix react-native polyfill to prevent multiple polyfills

packages/react-native-lightning/src/plugins/reactNativePolyfillsPlugin.ts

@@ -41,10 +41,11 @@ function tryFindFocusManager(
   return null;
 }
 
+let polyfilled = false;
+
 export const reactNativePolyfillsPlugin = (): Plugin => {
   // Track the single FocusManager instance
   let focusManager: FocusManager<LightningViewElement> | null = null;
-  let polyfilled = false;
 
   return {
     async init() {