[base-controller] Rename `ListenerV2` to `StateChangeListener`

[Gudahtt]

The state change listener type is still exported as ListenerV2, back from when all of our exports were suffixed with V2 because of the two different BaseController versions. We forgot to drop the V2 from this export when we dropped it from the others. Also this name is less descriptive than our other exports (it's not clear which lister it represents).

We should rename it to StateChangeListener, so that it's more clear what it is, and so that the obsolete "V2" is gone.

This will be a breaking change, so we will be grouping it with the breaking changes from #5626