Have UpgradeWallet take the version to upgrade to and an error message out parameter

Summary:
Backport of Core PR15761 [3/6] : https://github.com/bitcoin/bitcoin/pull/15761/commits/c988f27937bc79c90f4eed48552c72f1b66dc044

Depends on D7923

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D7924