Fix crash AssertNotNull (wix#2148)

Author: kyunkakata

lib/android/src/main/java/com/wix/reactnativeuilib/keyboardinput/utils/RuntimeUtils.java

@@ -14,15 +14,19 @@ public void run() {
     };
 
     public static void runOnUIThread(Runnable runnable) {
-        ReactContextHolder.getContext().runOnUiQueueThread(runnable);
+        if (ReactContextHolder.getContext() != null) {
+            ReactContextHolder.getContext().runOnUiQueueThread(runnable);
+        }
     }
 
     public static void dispatchUIUpdates(final Runnable userRunnable) {
         runOnUIThread(new Runnable() {
             @Override
             public void run() {
                 userRunnable.run();
-                ReactContextHolder.getContext().runOnNativeModulesQueueThread(sUIUpdateClosure);
+                if (ReactContextHolder.getContext() != null) {
+                    ReactContextHolder.getContext().runOnNativeModulesQueueThread(sUIUpdateClosure);
+                }
             }
         });
     }