Fix runOnMainThread to run at front of queue (#7792)

Author: yogevbd

lib/android/app/src/main/java/com/reactnativenavigation/utils/UiUtils.java

@@ -82,9 +82,9 @@ public void onWindowDetached() {
 
     public static void runOnMainThread(Runnable runnable) {
         if (Looper.myLooper() == Looper.getMainLooper()) {
-            new Handler(Looper.getMainLooper()).postAtFrontOfQueue(runnable);
+            runnable.run();
         } else {
-            new Handler(Looper.getMainLooper()).post(runnable);
+            new Handler(Looper.getMainLooper()).postAtFrontOfQueue(runnable);
         }
     }