Repository: flutter
Issue: [go_router] Expose Navigator.clipBehavior to ShellRoute
Labels: package,has reproducible steps,P3,p: go_router,found in release: 3.10,team-go_router,triaged-go_router,found in release: 3.13

### 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

When adding padding to the builder of a MaterialApp, you can see that the router clips its children. This is demonstrated best by creating a GoRoute with a big box shadow.

This gets problematic when using a ShellRoute, where a child route has a container with a box shadow. The box shadow gets clipped, looks off and does not fulfil the requirements of the design team.

To experience this behavior firsthand, you can test the code sample provided below.

### Expected results

The box shadow should spread in all directions.

### Actual results

The box shadow only spreads left and top and is clipped right and bottom.

### Code sample

<details><summary>Basic code sample</summary>

```dart
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: 'Flutter Demo',
      builder: (context, child) => Padding(
        padding: const EdgeInsets.all(32),
        child: child,
      ),
      routerConfig: GoRouter(
        routes: [
          GoRoute(
            path: "/",
            builder: (context, state) => Container(
              margin: const EdgeInsets.only(left: 100, top: 100),
              decoration: const BoxDecoration(
                color: Colors.red,
                boxShadow: [
                  BoxShadow(
                    blurRadius: 50,
                    offset: (Offset(20, 20)),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}
```

</details>

<details><summary>Code sample in the context of a ShellRoute</summary>

``` dart
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: 'Flutter Demo',
      routerConfig: GoRouter(
        routes: [
          ShellRoute(
            builder: (context, state, child) => MyHomePage(child: child),
            routes: [
              GoRoute(
                path: "/",
                builder: (context, state) => const MySubPage(),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

class MyHomePage extends StatelessWidget {
  final Widget child;

  const MyHomePage({
    super.key,
    required this.child,
  });

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Row(
        children: [
          Container(
            width: 100,
            color: Colors.green,
          ),
          Expanded(
            child: Padding(
              padding: const EdgeInsets.all(32),
              child: child,
            ),
          ),
        ],
      ),
    );
  }
}

class MySubPage extends StatelessWidget {
  const MySubPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(top: 100),
      decoration: const BoxDecoration(
        color: Colors.red,
        boxShadow: [
          BoxShadow(
            blurRadius: 50,
            offset: (Offset(20, 20)),
          ),
        ],
      ),
    );
  }
}
```

</details>

### Screenshots or Video

<details>
<summary>Screenshots / Video demonstration</summary>

<img width="939" alt="Screenshot 2023-08-03 at 11 05 50" src="https://github.com/flutter/flutter/assets/71591438/93af62a7-5786-4e5e-bb56-24b6e2695960">


</details>


### Logs

<details><summary>Logs</summary>

[log.txt](https://github.com/flutter/flutter/files/12249300/log.txt)

</details>


### Flutter Doctor output

<details><summary>Doctor output</summary>

```console
[✓] Flutter (Channel stable, 3.10.5, on macOS 13.3.1 22E772610a darwin-arm64, locale en-DE)
    • Flutter version 3.10.5 on channel stable at /Users/[user]/Development/src/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 796c8ef792 (7 weeks ago), 2023-06-13 15:51:02 -0700
    • Engine revision 45f6e00911
    • Dart version 3.0.5
    • DevTools version 2.23.1

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
    • Android SDK at /Users/[user]/Library/Android/sdk
    • Platform android-33, build-tools 33.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 14.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14E300c
    • CocoaPods version 1.12.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2021.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)

[✓] VS Code (version 1.80.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.70.0

[✓] Connected device (2 available)
    • macOS (desktop) • macos  • darwin-arm64   • macOS 13.3.1 22E772610a darwin-arm64
    • Chrome (web)    • chrome • web-javascript • Google Chrome 115.0.5790.114

[✓] Network resources
    • All expected network resources are available.

• No issues found!
```

</details>