adding NiaApp layout preview

[diverdan92]

Made it so that the NiaApp Composable shows a full layout preview that mimics the first app layout that a user will see when launching the app (the topics screen). Also added reference device multi preview that matches reference devices elsewhere in Studio (Layout Editor, Layout Validation, etc...)

[dturner]

@diverdan92 Please could you fix the build issue (try adding the :core:domain repository), and the merge conflicts.

[mmoczkowski]

Closing due to inactivity. If you still want to merge this change, please create a new PR

[dturner]

I'm reopening this because it's pretty important that previewing the app works correctly, especially on large screens.

[alexvanyo]

A change was just merged to navigation where this should work without needing the LocalInspectionMode changes on our side: https://android-review.googlesource.com/2423106.

Once we've updated to a version with that change, adding previews should work directly.

[mmoczkowski]

@alexvanyo has the version been updated already?

[alexvanyo]

Not yet, looks like we're on 2.5.3 still, and this was first released in 2.6.0-alpha06

[mmoczkowski]

Closing this PR since this change won't be required after nav library update.