Add an API that lets consumers wait on dependency node to be up-to-date with a given project version

Similar to: https://github.com/dotnet/project-system/issues/3425.

We need an API that lets consumers wait on the dependency node to be up-to-date with a given project version, similar to IProjectTreeService.PublishTree:

``` C#
Task PublishLatestAsync(CancellationToken cancellationToken = default(CancellationToken));

Task PublishAsync(IImmutableDictionary minimumRequiredDataSourceVersions, CancellationToken cancellationToken = default(CancellationToken));
```

This lets us block VS integration tests on this work before attempting to test state. Without this its impossible to determine when the dependency node has finished work.