Update xunit-dotnet monorepo to 2.9.3

Author: renovate[bot]

Tests/Directory.Build.props

@@ -10,7 +10,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.2" />
     <PackageReference Include="Microsoft.TestPlatform.ObjectModel" Version="17.7.2" />
     <PackageReference Include="Moq" Version="4.20.69" />
-    <PackageReference Include="xunit" Version="2.5.1" />
+    <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" PrivateAssets="All" Version="2.5.1">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>