Bump Microsoft.NET.Test.Sdk from 16.8.3 to 16.9.4 (#1223)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.8.3 to 16.9.4.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](https://github.com/microsoft/vstest/compare/v16.8.3...v16.9.4)

Signed-off-by: dependabot[bot] <[email protected]>

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

UnitTests/UnitTests.csproj

@@ -14,7 +14,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
     <PackageReference Include="System.Collections" Version="4.3.0" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">