Error when running a WinUI Unpackaged app in Visual Studio 2022

### Describe the bug

Hi,

When I try to run a WInUI app in Visual Studio 2022 Community Version 17.12.0 in "Unpackaged" mode I get the following error:

System.Runtime.InteropServices.COMException
HResult=0x80040154
Message=Class not registered (0x80040154 (REGDB_E_CLASSNOTREG))
Source=System.Private.CoreLib
StackTrace:
at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode)
at WinRT.ActivationFactory.Get(String typeName, Guid iid)
at Microsoft.UI.Xaml.Application.get__objRef_global__Microsoft_UI_Xaml_IApplicationStatics()
at Microsoft.UI.Xaml.Application.Start(ApplicationInitializationCallback callback)
at App4.Program.Main(String[] args) in G:\Data\Users\Ward\Documents\Visual_Studio_Projects\App4\obj\x64\Debug\net8.0-windows10.0.19041.0\win-x64\App.g.i.cs:line 26

This happens if I have it set to either x86 / x64.

The project type I create is: "Blank App, Packaged (WinUI 3 in Desktop)"

Note If I run it as a packaged app it runs without issue.

Thanks
Ward



### Steps to reproduce the bug

In Visual Studio 2022 - create a project of type: "Blank App, Packaged (WinUI 3 in Desktop)".

Then set the package type to: (Unpackaged)

### Expected behavior

_No response_

### Screenshots

_No response_

### NuGet package version

None

### Windows version

_No response_

### Additional context

_No response_

Reproduce the failure from a Visual Studio 2022 "Blank App, Packaged (WinUI 3 in Desktop)" project after switching it to Unpackaged mode, using the x86 and x64 configurations. Start at App.g.i.cs line 26 and compare the unpackaged and packaged runs; done means the unpackaged app starts without the 0x80040154 Class not registered exception.

Written by the indexing model from the issue text.