fix: removed react native async storage package from utils. (#536)

Summary:

Keeping React Native specific implementation in utils makes optimizely-sdk expect react native peer dependencies installed even in case of browser and node. Removed React Native specific cache implementation from utils.

Test plan:

All Existing tests should pass

Author: zashraf1985

packages/utils/__mocks__/@react-native-community/async-storage.ts

@@ -45,10 +45,6 @@
     "@types/uuid": "^3.4.4",
     "jest": "^23.6.0",
     "ts-jest": "^23.10.5",
-    "typescript": "^3.3.3333",
-    "@react-native-community/async-storage": "^1.2.0"
-  },
-  "peerDependencies": {
-    "@react-native-community/async-storage": "^1.2.0"
+    "typescript": "^3.3.3333"
   }
 }

packages/utils/__tests__/reactNativeAsyncStorageCache.spec.ts

@@ -155,6 +155,3 @@ export enum NOTIFICATION_TYPES {
 export interface NotificationCenter {
   sendNotifications(notificationType: NOTIFICATION_TYPES, notificationData?: any): void
 }
-
-export { default as PersistentKeyValueCache } from './persistentKeyValueCache'
-export { default as ReactNativeAsyncStorageCache } from './reactNativeAsyncStorageCache'