Toolkit Gallery: Link to `GridSplitter` on `ContentSizer` page is broken

### Describe the bug

Hi, on the `ContentSizer` page of Windows Community Toolkit Gallery, there is a link to `GridSplitter`. This Link is broken.

This link is right at the beginning of the page `Controls\Sizers\ContentSizer`, in the sentence `If you're using a Grid, use GridSplitter instead`.

Clicking the given link to `GridSplitter` page causes an error pop-up.

### Steps to reproduce

```text
1. In the `Windows Community Toolkit Gallery` app, navigate to page `Controls\Sizers\ContentSizer`
2. Right at the beginning of the page, you'll find the introduction `If you're using a Grid, use GridSplitter instead`
3. Click `GridSplitter` right in this sentence to get the mentioned error message
```

### Expected behavior

The app should navigate to `GridSplitter` page.

### 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

24H2 OS build 26120.3380

### 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

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

Windows Community Toolkit Gallery アプリを開き、Controls\Sizers\ContentSizer に移動します。導入文にある GridSplitter リンクを確認し、リンク先を修正して、エラーポップアップが表示されずに GridSplitter ページが開くことを確認します。

索引モデルが issue の本文から書いたものです。