[backport#17304 12/18] Refactor: Move MarkUnusedAddresses code out of CWallet::AddToWalletIfInvolvingMe

Summary:
This commit does not change behavior.

https://github.com/bitcoin/bitcoin/pull/17304/commits/46865ec958b6b9bde04a827de598975f14bdb5e7

Depends on D7158

Partial backport of Core PR17304

Test Plan:

ninja check

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Differential Revision: https://reviews.bitcoinabc.org/D7159