FrameworkElement.Margin exception SegmentedItem

### Describe the bug

Application crash when `Segmented` use `ItemTemplate`

```xml

```

### Steps to reproduce

```text
1. Declare data template, with SegmentedItem inside
2. Hook the data template woth the `Segmented` control
3. Applicaiton crash with exception

Failed to assign to property 'Microsoft.UI.Xaml.FrameworkElement.Margin'. [Line: 0 Position: 0] there is no binding error here is the template
```

### Expected behavior

Application run successfully

### 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)
- [x] Windows 11 21H2 (Build 22000)
- [ ] Other (specify)

### Other Windows Build number

_No response_

### App minimum and target SDK version

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

### Other SDK version

_No response_

### Visual Studio Version

2022

### Visual Studio Build Number

_No response_

### Device form factor

Desktop

### Additional context

_No response_

### Help us help you

Yes, I'd like to be assigned to work on this item.

Start by locating the Segmented and SegmentedItem control implementations and reproduce the issue with the provided DataTemplate on WinUI 3. Trace the FrameworkElement.Margin assignment that occurs when ItemTemplate is applied. Done means the sample runs successfully without the Margin exception, with a regression test if the existing control tests cover this scenario.

索引モデルが issue の本文から書いたものです。