Remove explicit package versions to comply with central package management

Author: guimafelipe

Samples/MultiHeadedPackage/cs/cs-winui-msix/PrimaryApp/PrimaryApp.csproj

@@ -12,8 +12,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.WindowsAppSDK" Version="1.5.240227000" />
-    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.22621.3233" />
+    <PackageReference Include="Microsoft.WindowsAppSDK" />
+    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" />
   </ItemGroup>
 
   <ItemGroup>