Stub nativeFabricUIManager for jest tests (#41408)

Summary:
Pull Request resolved: #41408

When FabricRenderer is used during jests it will currently error out since `nativeFabricUIManager` is nog a configured global.

Changelog: [Internal]

Reviewed By: christophpurrer

Differential Revision: D51198314

fbshipit-source-id: 4db1450f6b36699311692c2cd467184f6abea518

Author: javache

packages/react-native/jest/setup.js

@@ -27,6 +27,12 @@ Object.defineProperties(global, {
     value: id => clearTimeout(id),
     writable: true,
   },
+  nativeFabricUIManager: {
+    configurable: true,
+    enumerable: true,
+    value: {},
+    writable: true,
+  },
   performance: {
     configurable: true,
     enumerable: true,