Repository: flutter
Issue: AppBar tint remains applied when using IndexedStack
Labels: framework,f: material design,f: scrolling,has reproducible steps,P2,team-design,triaged-design,found in release: 3.16,found in release: 3.18

### Is there an existing issue for this?

- [X] I have searched the [existing issues](https://github.com/flutter/flutter/issues)
- [X] I have read the [guide to filing a bug](https://flutter.dev/docs/resources/bug-reports)

### Steps to reproduce

1. Create an `IndexedStack` where at least 1 page is scrollable.
2. Scroll that page so the app bar has tint applied.
3. Go to another index on the `IndexedStack`

### Expected results

The app bar should have its tint cleared, because there is no scrolled container in the view.

### Actual results

The app bar remains with tint, even the new content is not scrollable or it is not scrolled.

When a second scrollable content is scrolled then it is scrolled back to the begin, then the tint disappears.

Widgets that changes the current viewport, such as tabs, indexed stacks, pageview, etc. should notify the appbar to reapply its tint, if necessary.

### Code sample

<details><summary>Code sample</summary>

```dart
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  int selectedIndex = 0;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text("Some title"),
        ),
        body: IndexedStack(
          index: selectedIndex,
          children: [
            SingleChildScrollView(
              padding: EdgeInsets.all(16),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  Text("Scroll me to the bottom, then press the button"),
                  Placeholder(fallbackHeight: 1500),
                  TextButton(
                    onPressed: () => setState(() => selectedIndex = 1),
                    child: Text("Press me"),
                  ),
                ],
              ),
            ),
            Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  Text("I'm not scrollable"),
                  TextButton(
                    onPressed: () => setState(() => selectedIndex = 2),
                    child: Text("Go to some scrollable content"),
                  ),
                  TextButton(
                    onPressed: () => setState(() => selectedIndex = 2),
                    child: Text("Go back to the first page"),
                  ),
                ],
              ),
            ),
            SingleChildScrollView(
              padding: EdgeInsets.all(16),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  Text("I am scrollable"),
                  Placeholder(fallbackHeight: 1500),
                  TextButton(
                    onPressed: () => setState(() => selectedIndex = 0),
                    child: Text("Home"),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

```

</details>


### Screenshots or Video

<details>
<summary>Screenshots / Video demonstration</summary>


https://github.com/flutter/flutter/assets/379339/6592c229-824a-473b-b716-ee8517e3f9e2



</details>


### Logs

_No response_

### Flutter Doctor output

<details><summary>Doctor output</summary>

```console
╰─ flutter doctor                                                                                                                                                                                                           Doctor summary (to see all details, run flutter doctor -v):
[!] Flutter (Channel stable, 3.16.2, on Microsoft Windows [Version 10.0.22631.2715], locale pt-BR)
    ! Warning: `flutter` on your path resolves to C:\Users\jckod\fvm\versions\3.16.2\bin\flutter, which is not inside your current Flutter SDK checkout at C:\Users\jckod\fvm\default. Consider adding
      C:\Users\jckod\fvm\default\bin to the front of your path.
    ! Warning: `dart` on your path resolves to C:\Users\jckod\fvm\versions\3.16.2\bin\dart, which is not inside your current Flutter SDK checkout at C:\Users\jckod\fvm\default. Consider adding
      C:\Users\jckod\fvm\default\bin to the front of your path.
[✓] Windows Version (Installed version of Windows is version 10 or higher)
[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
[✓] Chrome - develop for the web
[✓] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.8.1)
[✓] Android Studio (version 2022.3)
[✓] VS Code (version 1.84.2)
[✓] Connected device (4 available)
[✓] Network resources

! Doctor found issues in 1 category.
```

</details>