Please add support to customize top margin of DragHandle

[svarup]

What feature would you like to see?

lib/src/widgets/wolt_bottom_sheet_drag_handle.dart

In above file margin: const EdgeInsets.only(top: 8.0), is set statically to 8.0, please allow to customize top margin, just like we have dragHandleSize or dragHandleColor using WoltModalSheetThemeData.