EarlGrey 2.0 | Expose GREY_REMOTE_CLASS_IN_APP to the swift tests

My use case: I'd like to know the main view currently shown to the user (ie. viewcontroller). This is useful, as the app I'm working with has an OOBE flow that only shows up the first time. I want to know if the app is in this first run experience.

After consulting with @tirodkar , his recommendation is to expose the GREY_REMOTE_CLASS_IN_APP (method?) to the Swift tests.

Here's an analogous line of ObjC he provided:
[[[[GREY_REMOTE_CLASS_IN_APP(UIApplication) sharedApplication] keyWindow] rootViewController] class]

Start by locating GREY_REMOTE_CLASS_IN_APP and the Swift test integration. Compare the available Swift-facing access with the analogous Objective-C expression using UIApplication, keyWindow, and rootViewController. Done means Swift tests can use the exposed functionality to identify the currently shown view controller.

Written by the indexing model from the issue text.