Add comment explaining "null" loggers for demo app

android/app/src/main/java/com/gutenberg/MainApplication.java

@@ -151,6 +151,7 @@ protected List<ReactPackage> getPackages() {
                         new ReactSliderPackage(),
                         new ReactVideoPackage(),
                         new SvgPackage(),
+                        // passing null because we do not need log handlers in the demo app
                         new ReactAztecPackage(null, null),
                         new LinearGradientPackage(),
                         mRnReactNativeGutenbergBridgePackage);