Set default font when creating defaut appStyle (#1053)

android/app/src/main/java/com/reactnativenavigation/params/parsers/StyleParamsParser.java

         result.topBarElevationShadowEnabled = true;
         result.titleBarHideOnScroll = false;
         result.orientation = Orientation.auto;
+        result.bottomTabFontFamily = new StyleParams.Font();
         return result;
     }