Repository: flutter
Issue: BottomAppBar notched shape does not accomodate current Material 3 FloatingActionButton
Labels: framework,f: material design,has reproducible steps,P3,team-design,triaged-design,found in release: 3.16,found in release: 3.17

### 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 repo using `flutter create --sample=material.BottomAppBar.2 mysample`
2. Run
3. Select any of the "Docked" positions for the Floating Action Button

### Expected results

The notch shape should accomodate the currently default shape for a Floating Action Button, which in Material 3 theme is a rounded square.

### Actual results

The notch shape does not actually accomodate the Floating Action Button correctly.

### Code sample

Use [BottomAppBar docs code block](https://api.flutter.dev/flutter/material/BottomAppBar-class.html#material.BottomAppBar.2)


### Screenshots or Video

<details>
<summary>Screenshot</summary>

![wrong notch shape](https://github.com/flutter/flutter/assets/4032522/bc33e4a1-70de-4972-8621-c9b5e556fa87)

</details>


### Logs

_No response_

### Flutter Doctor output

<details><summary>Doctor output</summary>

```console
[✓] Flutter (Channel stable, 3.16.0, on macOS 14.1.1 23B81 darwin-arm64, locale es-ES)
    • Flutter version 3.16.0 on channel stable at /Users/jago/dev/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision db7ef5bf9f (11 days ago), 2023-11-15 11:25:44 -0800
    • Engine revision 74d16627b9
    • Dart version 3.2.0
    • DevTools version 2.28.2

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.2)
    • Android SDK at /Users/jago/Library/Android/sdk
    • Platform android-33, build-tools 33.0.2
    • ANDROID_HOME = /Users/jago/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b829.9-10027231)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.0.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 15A507
    • CocoaPods version 1.13.0

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2022.3)
    • 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 17.0.6+0-17.0.6b829.9-10027231)

[✓] VS Code (version 1.84.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.76.0

[✓] Connected device (3 available)
    • sdk gphone64 arm64 (mobile) • emulator-5554 • android-arm64  • Android 13 (API 33) (emulator)
    • macOS (desktop)             • macos         • darwin-arm64   • macOS 14.1.1 23B81 darwin-arm64
    • Chrome (web)                • chrome        • web-javascript • Google Chrome 119.0.6045.159

[✓] Network resources
    • All expected network resources are available.

• No issues found!
```

</details>