Add Option to allow target's default behaviour

[pawanbangar]

Is your feature request related to a problem? Please describe. I am focusing showcaseview on column which has 5 radio button, i want user to select one of them, but i am not able to select as i can't allow target area to clickable

Describe the solution you'd like Inside lib/src /showcase.dart

If we add option to change behavior (HitTestBehavior.translucent) It will be helpoful

 Widget targetWidgetContent() {
    return GestureDetector(
      onTap: onTap,
      onLongPress: onLongPress,
      onDoubleTap: onDoubleTap,
      behavior: HitTestBehavior.translucent,
      child: Container(
        height: size.height,
        width: size.width,
        margin: targetPadding,
        decoration: ShapeDecoration(
          shape: radius != null
              ? RoundedRectangleBorder(borderRadius: radius!)
              : shapeBorder,
        ),
      ),
    );
  }

Describe alternatives you've considered I don't find alternative as we can click on target if and only if target is normal container which can i have only one clickable element.

Additional context

i feel this is happening because of this fixed PR https://github.com/SimformSolutionsPvtLtd/flutter_showcaseview/pull/412 @aditya-css