[backport#16399 1/3] Place out args at the end for CreateWallet

Summary:
https://github.com/bitcoin/bitcoin/pull/16399/commits/3199610ad3b93b849f2cb55a8ed3a39a32bbdffc

note: this one has already been added in D6425

Partial backport of Core PR16399

Test Plan:

ninja check check-functional

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D7035