[backport#16237 3/3] Add GetNewChangeDestination for getting new change Destinations

Summary:
Adds a GetNewChangeDestination that has the same objective as GetNewDestination

https://github.com/bitcoin/bitcoin/pull/16237/commits/8e7f930828a9f8f9be1c90ff45e3fdfef1980eaf

Depends on D6717

Concludes backport of Core PR16237

Test Plan:

ninja check-all

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D6721