[nuget] Bump Microsoft.NET.Test.Sdk from 18.3.0 to 18.5.0 (#1502)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Directory.Packages.props

@@ -10,7 +10,7 @@
     <PackageVersion Include="OneOf.Extended" Version="3.0.271" />
     <PackageVersion Include="System.Text.Json" Version="10.0.6" />
     <!-- Test packages (aligned across both quickstarts) -->
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.0" />
     <PackageVersion Include="xunit" Version="2.9.3" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
     <PackageVersion Include="coverlet.collector" Version="10.0.0" />