WrapLayout "collapsing"

### Describe the bug

I have a weird bug that unfortunately mighe be difficult to find. Im using the WinUI-ItemsRepeater with a WrapLayout as "ItemsRepeater.Layout" like this:

[...]

Now it seems that adding Elements in a long list when the ItemsRepeater is "scrolled down", then it "collapses" and renders the Items wrong. I unfortunately have no other repro than this video:

https://github.com/user-attachments/assets/aa7b6ff4-2ce0-43b9-a892-f55279af9fbf

Whenever it blinks blue, I'm adding a test-element (via right-click). I'm scrolling down while I do this. Once I reach a certain point, adding another element (or basically "modifiying the underlying collection") leads to a collaps of all (!) WrapLayout within that control. I have three of them in here and they all do collapse.

I'm assuming that the renderer crashes for whatever reason. Or the layout calculation gets corrupted. I hope some of you with deeper knowledge of the insights might get a clue what's happening here. Basically all Items in all visible WrapLayouts/ItemsRepeater do not get rendered once after the other but all get rendered at (0,0):


### Steps to reproduce

```text
Unfortunately I do not have a repro outside of my app.
```

### Expected behavior

I should be able to add elements as I wish without the layout collapsing.

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

### Other SDK version

_No response_

### Visual Studio Version

2022

### Visual Studio Build Number

17.4

### Device form factor

Desktop

### Additional context

_No response_

### Help us help you

No, I'm unable to contribute a solution.

ItemsRepeater.Layout として使用されている WinAppSDK/WinUI 3 WrapLayout から始め、基になるコレクションを変更しながらスクロールして失敗を再現します。動画とスクリーンショットを動作の参考として使用し、折りたたみの前後でレイアウトを比較します。要素を追加した後も、影響を受けるすべての WrapLayouts で表示されている項目が正しく配置されたままになれば完了です。

索引モデルが issue の本文から書いたものです。