Bump MSTest (#1426)

Bumps the dotnet group in /docs/fundamentals/snippets/testing/mstest with 1 update: [MSTest](https://github.com/microsoft/testfx).


Updates `MSTest` from 3.4.3 to 3.5.0
- [Release notes](https://github.com/microsoft/testfx/releases)
- [Changelog](https://github.com/microsoft/testfx/blob/main/docs/Changelog.md)
- [Commits](microsoft/testfx@v3.4.3...v3.5.0)

---
updated-dependencies:
- dependency-name: MSTest
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: dotnet
...

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

docs/fundamentals/snippets/testing/mstest/AspireApp.Tests/AspireApp.Tests.csproj

@@ -15,7 +15,7 @@
 
   <ItemGroup>
     <PackageReference Include="Aspire.Hosting.Testing" Version="8.1.0" />
-    <PackageReference Include="MSTest" Version="3.4.3" />
+    <PackageReference Include="MSTest" Version="3.5.0" />
   </ItemGroup>
 
   <ItemGroup>