Fix: cannot access context in onSwipe when no cards left then "destroy" the widget tree

[husainazkas]

Description

Step to Reproduce Issue:

1. Create a StatefulWidget for a page:

class FirstPage extends StatefulWidget {
  ...
}

class _FirstPageState extends State<FirstPage> {
  final List<Model> datas = [
    ...
  ];

  int currentIndex = 0;

  @override
  Widget build(BuildContext context) {
    return currentIndex == (datas.length - 1)
      ? NoDataLeft() // Another widget to show no data message
      : MyCards(
          datas: datas,
          onLiked: (index) {
            currentIndex = index;
            setState(() {});
          },
        );
    }
}

2. Create a single common widget

class MyCards extends StatelessWidget {
  final List<Model> datas;
  final ValueChanged<int> onLiked;

  const MyCards({super.key, required this.datas, required this.onLiked});

  @override
  Widget build(BuildContext context) {
    return CardSwiper(
      onSwipe: (previousIndex, currentIndex, direction) {
        // If the last card swiped and disposed, this block cannot access context's inheritance anymore
        // For example:
        context.read<MyProvider>();
      },
      cardsCount: widget.items.length,
      cardBuilder: (context, index, xPercent, yPercent) {
        return MyCardItemView(
          onLiked: () {
            onLiked(index);
          },
        );
      },
    );
  }
}

Error will appears and points to card_swiper.dart line 251.

This PR will fix the issue, just to arrange order when to call super.dispose().

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style.
• I updated/added relevant documentation (doc comments with ///).
• All existing and new tests are passing.

Visual reference

[ricardodalarme]

thank you!