[fix] add UIManager to NativeModules

packages/react-native-web/src/exports/NativeModules/index.js

@@ -1,3 +1,17 @@
+/**
+ * Copyright (c) 2016-present, Nicolas Gallagher.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @noflow
+ */
+
+import UIManager from '../UIManager';
+
 // NativeModules shim
-const NativeModules = {};
+const NativeModules = {
+  UIManager
+};
+
 export default NativeModules;

packages/react-native-web/src/exports/UIManager/index.js

@@ -97,7 +97,10 @@ const UIManager = {
 
   configureNextLayoutAnimation(config, onAnimationDidEnd) {
     onAnimationDidEnd();
-  }
+  },
+
+  // mocks
+  setLayoutAnimationEnabledExperimental() {}
 };
 
 export default UIManager;