ButtonBarButton on set data function need to dispatch FlexEvent dataChange

Since I've updated to Flex SDK 4.16. I got a crash when using RichTextEditor.

The issue seems to be that in the class spark.components.ButtonBarButton on set data function, it dispatch dispatchEvent(new Event("dataChange")). It should dispatch FlexEvent instead of Event.

This cause various class that listen to the FlexEvent.DATA_CHANGE to error because it's expecting it to be FlexEvent class instead of Event class