Fix last import ordering lint error in CrossLinkRegistryTests

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: Mpdreamz

tests/Elastic.Documentation.Configuration.Tests/CrossLinkRegistryTests.cs

@@ -6,12 +6,12 @@
 using System.IO.Abstractions;
 using System.IO.Abstractions.TestingHelpers;
 using AwesomeAssertions;
-using Nullean.ScopedFileSystem;
 using Elastic.Documentation.Configuration.Builder;
 using Elastic.Documentation.Configuration.Products;
 using Elastic.Documentation.Configuration.Toc;
 using Elastic.Documentation.Configuration.Versions;
 using Elastic.Documentation.Diagnostics;
+using Nullean.ScopedFileSystem;
 
 namespace Elastic.Documentation.Configuration.Tests;