ASP.NET Core client side Blazor applications can't be run in VSCode

This was originally reported over in https://github.com/aspnet/AspNetCore/issues/9451 and it seems that the dialog to add build assets to the project can't detect Blazor client side applications because they're not true runnable applications on their own.

To fix this there's two steps:
1. Make runnable project detection understand Blazor client side applications
2. Update the run .net core console app to utilize `dotnet run --no-build` instead of `dotnet *.dll`. The distinction about using `dotnet run` enables the Blazor project to hijack the run process and properly boot a runnable application.

/cc @danroth27