SettingsExpander in SettingsExpander crashes the application

### Describe the bug

If you define a `SettingsExpander` as an item within another `SettingsExpander`, the application crashes.
```xml

```

### Steps to reproduce

```text
1. Add a `SettingsExpander` to the layout.
2. Add another `SettingsExpander` as a nested item inside the first `SettingsExpander`.
3. Run the application.
4. Observe that the application crashes.
```

### Expected behavior

The application should not crash.
- Automatically hide/not render the nested `SettingsExpander`.
- Alternatively, the build process could prevent such layout from compiling/add hint.
- Explicitly marking nested SettingsExpander usage as prohibited in the gallery documentation.

### Screenshots

_No response_

### Code Platform

- [ ] UWP
- [x] WinAppSDK / WinUI 3
- [ ] Web Assembly (WASM)
- [ ] Android
- [ ] iOS
- [ ] MacOS
- [ ] Linux / GTK

### Windows Build Number

- [ ] Windows 10 1809 (Build 17763)
- [ ] Windows 10 1903 (Build 18362)
- [ ] Windows 10 1909 (Build 18363)
- [ ] Windows 10 2004 (Build 19041)
- [ ] Windows 10 20H2 (Build 19042)
- [ ] Windows 10 21H1 (Build 19043)
- [ ] Windows 10 21H2 (Build 19044)
- [ ] Windows 10 22H2 (Build 19045)
- [ ] Windows 11 21H2 (Build 22000)
- [x] Other (specify)

### Other Windows Build number

Windows 11 24H2 (Build 26100)

### App minimum and target SDK version

- [ ] Windows 10, version 1809 (Build 17763)
- [ ] Windows 10, version 1903 (Build 18362)
- [ ] Windows 10, version 1909 (Build 18363)
- [ ] Windows 10, version 2004 (Build 19041)
- [ ] Windows 10, version 2104 (Build 20348)
- [x] Windows 11, version 22H2 (Build 22000)
- [ ] Other (specify)

### Other SDK version

_No response_

### Visual Studio Version

Preview

### Visual Studio Build Number

17.12.0 Preview 5.0

### Device form factor

Desktop

### Additional context

**CommunityToolkit.WinUI.Controls.SettingsControls**: `8.1.240916`

### Help us help you

No, I'm unable to contribute a solution.