Added content view to fragmentScreen with zero dimensions, so that it affects styling

android/app/src/main/java/com/reactnativenavigation/screens/FragmentScreen.java

         content = new FrameLayout(getContext());
         content.setId(ViewUtils.generateViewId());
         ContentView contentView = new ContentView(getContext(), screenParams.screenId, screenParams.passProps, screenParams.navigationParams, null);
+        addView(contentView, 0, 0);
         addView(content, addBelowTopBar());
         addFragment();
         contentView.init();