Fix MSB3277 “WindowsBase” conflicts in dev apps by enabling WPF build ref

[gladjohn]

Fixes - Build warning

  22>C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2433,5): warning MSB3277: Found conflicts between different versions of "WindowsBase" that could not be resolved. [D:\a\1\s\tests\devapps\WinFormsTestApp\WinFormsTestApp.csproj]
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2433,5): warning MSB3277: There was a conflict between "WindowsBase, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" and "WindowsBase, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35". 

Changes proposed in this request
After recent Desktop/UI changes (and newer WebView2), several SDK‑style dev/test projects (e.g., NetCoreWinFormsWAM, the net8.0-windows target of NetFxConsoleApp) began emitting MSB3277 warnings due to a reference‑graph conflict between WindowsBase 4.0.0.0 (facade from Microsoft.NETCore.App.Ref) and WindowsBase 5.0.0.0 (required by Microsoft.Web.WebView2.Wpf.dll).

This PR resolves the conflict by enabling WPF build references in the affected SDK‑style projects so WindowsBase unifies to the desktop pack version.

Note: This does not “turn the app into a WPF UI.” It only opts the project into WPF framework references so the assembly graph is consistent. Apps remain WinForms/console unless XAML is actually added.

Testing
n/a

Performance impact
n/a

Documentation

• All relevant documentation is updated.

[Copilot]

Pull Request Overview

This PR fixes MSB3277 build warnings caused by conflicts between different versions of WindowsBase assemblies (4.0.0.0 vs 5.0.0.0) in SDK-style development/test projects. The conflict arises from the interaction between Microsoft.NETCore.App.Ref and Microsoft.Web.WebView2.Wpf.dll dependencies.

• Adds <UseWPF>true</UseWPF> property to affected SDK-style project files
• Enables WPF build references to unify WindowsBase to the desktop pack version
• Resolves assembly reference conflicts without changing the application UI framework

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
tests/devapps/WinFormsTestApp/WinFormsTestApp.csproj	Adds UseWPF property to resolve WindowsBase conflicts in WinForms test app
tests/devapps/WAM/NetCoreWinFormsWam/NetCoreWinFormsWAM.csproj	Adds UseWPF property to resolve WindowsBase conflicts in WinForms WAM test app
tests/devapps/NetFxConsoleTestApp/NetFxConsoleApp.csproj	Adds UseWPF property to resolve WindowsBase conflicts in console test app
tests/devapps/Net5TestApp/Net5TestApp.csproj	Adds UseWPF property to resolve WindowsBase conflicts in Net5 test app

[trwalke]

Seems like the warnings are gone. Thanks @gladjohn