Bump Microsoft.NET.Test.Sdk from 16.8.3 to 16.9.1 (PowerShell#14895)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.8.3 to 16.9.1.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](microsoft/vstest@v16.8.3...v16.9.1)

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

Author: dependabot[bot]

test/xUnit/xUnit.tests.csproj

@@ -27,7 +27,7 @@
     <PackageReference Include="Xunit.SkippableFact" Version="1.4.13" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
     <PackageReference Include="XunitXml.TestLogger" Version="3.0.62" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
   </ItemGroup>
 
   <ItemGroup>