Bump Microsoft.NET.Test.Sdk from 16.9.1 to 16.9.4

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.9.1 to 16.9.4.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](microsoft/vstest@v16.9.1...v16.9.4)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

examples/Xunit.Microsoft.DependencyInjection.ExampleTests/Xunit.Microsoft.DependencyInjection.ExampleTests.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
     <PackageReference Include="coverlet.collector" Version="3.0.3" />