Bump MSTest.TestFramework from 2.2.10 to 4.0.2

---
updated-dependencies:
- dependency-name: MSTest.TestFramework
  dependency-version: 4.0.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

samples/snippets/csharp/getting_started/ClassLibraryProjects/StringLibraryTest/StringLibraryTest.csproj

@@ -8,7 +8,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
-    <PackageReference Include="MSTest.TestFramework" Version="2.2.10" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.0.2" />
     <PackageReference Include="MSTest.TestAdapter" Version="2.2.10" />
     <PackageReference Include="coverlet.collector" Version="3.1.2" />
   </ItemGroup>