Add Microsoft.Testing.Extensions.CodeCoverage package

Added Microsoft.Testing.Extensions.CodeCoverage package version 18.4.1 for enhanced code coverage support.

Author: glennawatson

src/Directory.Packages.props

@@ -9,6 +9,7 @@
     <PackageVersion Include="TUnit" Version="1.12.125" />
     <PackageVersion Include="Verify.TUnit" Version="31.11.0" />
     <PackageVersion Include="Verify.SourceGenerators" Version="2.5.0" />
+    <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.4.1" />
 
     <!-- Roslyn / Code Analysis - All projects use 4.14.0 for compatibility -->
     <PackageVersion Include="Microsoft.CodeAnalysis.Analyzers" Version="3.11.0" />