refs and cleanup

Author: SimonCropp

src/Directory.Packages.props

@@ -7,7 +7,7 @@
     <PackageVersion Include="Magick.NET-Q16-AnyCPU" Version="14.11.1" />
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.2" />
     <PackageVersion Include="Microsoft.AspNetCore.TestHost" Version="10.0.5" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
     <PackageVersion Include="Microsoft.Playwright" Version="1.58.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="6.2.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.172" />