Native AOT: InvalidCastException when using GridSplitter

### Describe the bug

I'm seeing this crash reported on a device with `Windows 10.0.19045`. I wasn't able to reproduce it locally on a Windows 11 machine
```
System.InvalidCastException: Specified cast is not valid
at System.Runtime.RuntimeExports.RhUnbox2(MethodTable*, Object) + 0x3f
at CommunityToolkit.WinUI.Controls.GridSplitter.IsStarColumn(ColumnDefinition) + 0x53
at CommunityToolkit.WinUI.Controls.GridSplitter.OnDragHorizontal(Double) + 0xf9
at CommunityToolkit.WinUI.Controls.SizerBase.OnManipulationDelta(ManipulationDeltaRoutedEventArgs) + 0x11b
at ABI.Microsoft.UI.Xaml.Controls.IControlOverrides.Do_Abi_OnManipulationDelta_15(IntPtr, IntPtr) + 0x58
```

I'm using `CommunityToolkit.WinUI.Controls.Sizers 8.2.241112-preview1` in a .NET9 WinUI3 app that is compiled using Native AOT

### Steps to reproduce
I'm essentially only using a GridSplitter and adjusting Grid.Row and Grid.Column in code

```text

```

### Expected behavior

No crash

### 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)
- [x] 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

2022

### 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.

Start with the GridSplitter.IsStarColumn and OnDragHorizontal entry points named in the stack trace, then reproduce the GridSplitter interaction in a Native AOT WinUI 3 app on Windows 10. Done means adjusting the splitter no longer throws InvalidCastException.

Scritto dal modello di indicizzazione a partire dal testo della issue.