Arcade-Validation should also test building using VS

Additionally from building using the SDK bootstrapped from the `tools.dotnet` we should also test building using the msbuild from VS to avoid regressions in that codepath.

[Description of how to enable this in global.json](https://github.com/dotnet/arcade/blob/56b5e5a9debc87b98c5dd394e8a72c916099d9d5/Documentation/ArcadeSdk.md#globaljson)

Have to consider that the global.json should only have the vs section for this one build job.