Align SettingsExpander inner content correctly when icon collapsed

### Describe the bug

Let's align inner content too; otherwise, it looks ugly when you collapse fully.

### Steps to reproduce

```text
1. Use calc app going to Settings page.
2. See the issue
```

### Expected behavior

Aligh to the furtherest left.

### Screenshots


### Code Platform

- [X] 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)
- [ ] 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

_No response_

### Visual Studio Build Number

_No response_

### Device form factor

_No response_

### Additional context

_No response_

### Help us help you

No, I'm unable to contribute a solution.

SettingsExpanderを完全に折りたたんだ状態でcalcアプリのSettingsページにある問題を再現し、その後コントロールのレイアウトコードを特定します。内部コンテンツの水平方向の配置を確認し、サポート対象のUWPおよびWinUIプラットフォームで折りたたんだときに最も左側に揃うことを確認します。

索引モデルが issue の本文から書いたものです。