Update deprecated getConstants() call (#1379)

This removes the React Native warning:

*Accessing view manager configs directly off UIManager via UIManager['getConstants'] is no longer supported. Use UIManager.getViewManagerConfig('getConstants') instead.*

Author: jarod-legault

src/handlers/createHandler.ts

@@ -43,11 +43,11 @@ UIManager.genericDirectEventTypes = {
   ...customGHEventsConfig,
 };
 // In newer versions of RN the `genericDirectEventTypes` is located in the object
-// returned by UIManager.getConstants(), we need to add it there as well to make
+// returned by UIManager.getViewManagerConfig('getConstants'), we need to add it there as well to make
 // it compatible with RN 61+
-if (UIManager.getConstants) {
-  UIManager.getConstants().genericDirectEventTypes = {
-    ...UIManager.getConstants().genericDirectEventTypes,
+if (UIManager.getViewManagerConfig) {
+  UIManager.getViewManagerConfig('getConstants').genericDirectEventTypes = {
+    ...UIManager.getViewManagerConfig('getConstants').genericDirectEventTypes,
     ...customGHEventsConfig,
   };
 }