Bug: TilesBrush not rendering correctly in WASDK compared to UWP

### Describe the bug

> Is there a known issue with TilesBrush? I copied the code and image from Windows Community Toolkit Gallery app and it doesn't work in a simple app. No error, but nothing displayed.
>
> 

### Steps to reproduce

```text
I was able to repro this bug in a blank WASDK app, and found that this issue is present in the WASDK version of the Gallery as well.

[TilesBrushWasdkBugTest.zip](https://origin.owlcore.io/ipfs/bafkreibvihky53onnwf5yezaujf6rv3jdsy4wbckeqhdrqck6s4oi3tk24?filename=TilesBrushWasdkBugTest.zip)
```

### Expected behavior

On Wasdk, we see:


It's not clear why this works on UWP but not Wasdk.

On UWP, we see:


### 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

- [ ] 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

Reported in the [`#community-toolkit`](https://discord.com/channels/372137812037730304/669640275500466197/1373160624686895216) channel in the Windows App Community.

### Help us help you

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

Comienza ejecutando el archivo TilesBrushWasdkBugTest.zip adjunto en una aplicación WinAppSDK/WinUI 3 vacía y compárala con los ejemplos de WASDK y UWP de Windows Community Toolkit Gallery. Traza el punto de entrada del renderizado de TilesBrush y reproduce la diferencia; se considera terminado cuando TilesBrush muestra la imagen teselada esperada en WASDK igual que en UWP, con una comprobación de regresión si el proyecto proporciona una.

Escrito por el modelo de indexación a partir del texto del issue.