`StickyHeaderBehavior` in conjuction with `ListView.GroupStyle`: The `GroupStyle` header covers sticky header

### Describe the bug

Th in conjuction with `ObservableGroup`


### Steps to reproduce

Basically use the example xaml from the _MVVM Toolkit Sample App_, and add the `StickyHeaderBehavior` based on the example in _Windows Community Toolkit Gallery_:

```xaml

```

### Expected behavior

The ListView header should cover (higher z-index) than the GroupStyle header.

### Screenshots


### 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

23H2

### 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

2022

### Visual Studio Build Number

17.9.6

### Device form factor

Desktop

### Additional context

Not sure if this is more of a https://github.com/microsoft/microsoft-ui-xaml issue.

### Help us help you

No, I'm unable to contribute a solution.