Don't double-add Extensions source project for tests when not needed

Author: michael-hawker

ProjectHeads/AllComponents/Tests.WinAppSdk/CommunityToolkit.Tests.WinAppSdk.csproj

@@ -4,7 +4,6 @@
     <IsDeployableHead>true</IsDeployableHead>
     <IsWinAppSdk>true</IsWinAppSdk>
     <HasWinUI>true</HasWinUI>
-    <HasWinUI>true</HasWinUI>
     <WinUIMajorVersion>3</WinUIMajorVersion>
   </PropertyGroup>
 

ProjectHeads/SingleComponent/Tests.Uwp/ProjectTemplate.Tests.Uwp.csproj

@@ -7,6 +7,8 @@
     <IsUwp>true</IsUwp>
     <HasWinUI>true</HasWinUI>
     <WinUIMajorVersion>2</WinUIMajorVersion>
+
+    <IsSingleExperimentHead>true</IsSingleExperimentHead>
   </PropertyGroup>
 
   <Import Project="$(ToolingDirectory)\MultiTarget\EnabledTargetFrameworks.props" />

ProjectHeads/SingleComponent/Tests.WinAppSdk/ProjectTemplate.Tests.WinAppSdk.csproj

@@ -5,6 +5,8 @@
     <IsWinAppSdk>true</IsWinAppSdk>
     <HasWinUI>true</HasWinUI>
     <WinUIMajorVersion>3</WinUIMajorVersion>
+
+    <IsSingleExperimentHead>true</IsSingleExperimentHead>
   </PropertyGroup>
 
   <Import Project="$(ToolingDirectory)\MultiTarget\EnabledTargetFrameworks.props" />

ProjectHeads/Tests.Head.props

@@ -19,11 +19,11 @@
         <PackageReference Include="CommunityToolkit.$(DependencyVariant).Extensions" Version="8.0.230801-preview"/>
       </ItemGroup>
     </When>
-    <Otherwise>
+    <When Condition="'$(IsSingleExperimentHead)' == 'true' and $(MSBuildProjectName.StartsWith('Extensions')) == 'false'">
       <ItemGroup>
         <ProjectReference Include="$(ToolkitExtensionSourceProject)"/>
       </ItemGroup>
-    </Otherwise>
+    </When>
   </Choose>
 
   <!-- Global Usings -->