SettingsCard ControlTemplate is also applied to Header, HeaderIcon and Description

### Describe the bug

This code:
```xaml

```
will render:

### Steps to reproduce
Use the code above.

### Expected behavior

`ContentTemplate` is applied only to the `Content`.


### 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)
- [ ] Other (specify)

### Other Windows Build number

_No response_

### App minimum and target SDK version

- [x] 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)
- [ ] Windows 11, version 22H2 (Build 22000)
- [ ] Other (specify)

### Other SDK version

_No response_

### Visual Studio Version

Preview

### Visual Studio Build Number

Version 17.13.0 Preview 2.1

### Device form factor

Desktop

### Additional context

The following is mentioned on the ControlPresenter's [doc](https://learn.microsoft.com/en-us/windows/windows-app-sdk/api/winrt/microsoft.ui.xaml.controls.contentpresenter?view=windows-app-sdk-1.6&WT.mc_id=%3Fwt.mc_id%3DMVP_356303):
> If the ContentPresenter is in the ControlTemplate of a ContentControl, the ContentPresenter behavior will implicitly bind to the ContentTemplate and Content properties of the templated ContentControl.

### Help us help you

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

まず、提供された XAML を SettingsCard ControlTemplate で再現し、リンク先の ContentPresenter ドキュメントに記載されている ControlPresenter の動作を確認します。ContentTemplate が Header、HeaderIcon、Description にどのように到達するかを追跡します。完了とは、テンプレートが Content にのみ適用され、その他のプロパティは通常どおりレンダリングされることを意味します。

索引モデルが issue の本文から書いたものです。