Incorrect diagnosis of RepaintBoundary usefulness in Widget inspector DevTool

还没有人认领这个 Issue。

### Description

I was watching [this part](https://youtu.be/PONvNV3u1Wg?si=l0AIiVsPY70pzKP4&t=2201) of a talk at by Craig Labenz where he explains about `RepaintBoundary` and gives an example of where not to use it. Later, he explains how to use the Widget inspector DevTool to diagnose whether a `RepaintBoundary` is useful.

I ran the code snippet and the DevTool says it's useful. That has to be a bug, right?


### Code sample

Code sample

```dart
import 'package:flutter/material.dart';

void main() {
runApp(const MainApp());
}

class MainApp extends StatelessWidget {
const MainApp({super.key});

@override
Widget build(BuildContext context) {
return const MaterialApp(
home: Scaffold(body: Center(child: Body())),
);
}
}

class Body extends StatefulWidget {
const Body({super.key});

@override
State createState() => _BodyState();
}

class _BodyState extends State {
Color color = Colors.red;
@override
Widget build(BuildContext context) {
return SizedBox(
width: 200,
height: 200,
child: GestureDetector(
onTap: () => setState(() {
if (color == Colors.red) {
color = Colors.blue;
} else {
color = Colors.red;
}
}),
child: ColoredBox(
color: color,
child: RepaintBoundary(child: ColoredBox(color: color)),
),
),
);
}
}

```

### DevTool screenshot (see highlighted area):
This is after 10 taps on the tappable widget.

首先，在 Widget inspector DevTool 中复现提供的 Dart 示例，并检查点击十次后 RepaintBoundary 的实用性结果。确定所报告的诊断是否不正确，并记录观察到的行为和预期结果，即视为完成。

由索引模型根据 Issue 内容生成。