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: