Custom painter Widgets are incorrectly rendered

[jenshor]

Description
When custom painter is used, the rendered output might look wrong.

Widgetbook:

Simulator:

Code for repro:

class MacroDailyLogCard extends StatelessWidget {
  const MacroDailyLogCard({Key? key, required this.child, this.height = 350}) : super(key: key);

  final Widget child;
  final double height;

  @override
  Widget build(BuildContext context) {
    final CmColorScheme scheme = CmTheme.of(context).colorScheme;

    return Container(
      height: height,
      width: 325,
      decoration: ShapeDecoration(
        shadows: <BoxShadow>[
          BoxShadow(
            offset: const Offset(0, 5),
            blurRadius: 15,
            color: CmColors.shadow.withOpacity(0.1),
          ),
        ],
        color: scheme.gray800,
        shape: CustomShape(),
      ),
      child: child,
    );
  }
}

class CustomShape extends ShapeBorder {
  @override
  EdgeInsetsGeometry get dimensions => EdgeInsetsDirectional.zero;

  @override
  Path getInnerPath(Rect rect, {TextDirection? textDirection}) {
    return Path();
  }

  @override
  Path getOuterPath(Rect rect, {TextDirection? textDirection}) {
    return Path()
      ..moveTo(rect.topLeft.dx, rect.topLeft.dy + 22)
      ..quadraticBezierTo(rect.topLeft.dx + 3, rect.topLeft.dy + 10, rect.topLeft.dx + 14, rect.top + 8)
      ..quadraticBezierTo(rect.width / 2, rect.top - 20, rect.topRight.dx - 14, rect.top + 8)
      ..quadraticBezierTo(rect.topRight.dx - 3, rect.topRight.dy + 10, rect.topRight.dx, rect.top + 22)
      ..lineTo(rect.bottomRight.dx, rect.bottomRight.dy - 22)
      ..quadraticBezierTo(rect.bottomRight.dx - 3, rect.bottomRight.dy - 10, rect.bottomRight.dx - 14, rect.bottom - 8)
      ..quadraticBezierTo(rect.width / 2, rect.bottom + 20, rect.bottomLeft.dx + 14, rect.bottom - 8)
      ..quadraticBezierTo(rect.bottomLeft.dx + 3, rect.bottomLeft.dy - 10, rect.bottomLeft.dx, rect.bottom - 22)
      ..close();
  }

  @override
  void paint(Canvas canvas, Rect rect, {TextDirection? textDirection}) {}

  @override
  ShapeBorder scale(double t) {
    return this;
  }
}

Expected Behavior
Render looks like in the simulator.

[jenshor]

Might be related to #164.