batches: add publicationStates to the applyPreview query

Created by: LawnGnome

Closes #23380 (closed).

The actual change here is pretty small: there's a new optional argument on the applyPreview query, and it gets plumbed through the resolver layers until we reach a point where we can annotate the rewired changeset spec with the desired publication state before determining the planned operations. Easy peasy.

The tests, on the other hand...

Basically, the unit tests for the resolver changes end up looking suspiciously like integration tests. I'm not particularly bothered by that: there is a unit test for the one thing that actually is separable, but the rest is all pretty tightly coupled because GraphQL. At least the test coverage is good? :crossed_fingers: