Bump MSTest.TestAdapter from 4.1.0 to 4.2.1

---
updated-dependencies:
- dependency-name: MSTest.TestAdapter
  dependency-version: 4.2.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Directory.Packages.props

@@ -14,7 +14,7 @@
     <PackageVersion Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="10.0.201" />
     <PackageVersion Include="Microsoft.CodeAnalysis.Workspaces.MSBuild" Version="5.3.0" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
-    <PackageVersion Include="MSTest.TestAdapter" Version="4.1.0" />
+    <PackageVersion Include="MSTest.TestAdapter" Version="4.2.1" />
     <PackageVersion Include="MSTest.TestFramework" Version="4.2.1" />
     <PackageVersion Include="System.CommandLine.DragonFruit" Version="0.4.0-alpha.25320.106" />
     <!-- Reference-only packages for test framework namespace resolution in analyzer tests -->