Merge #18546: Bugfix: Wallet: Safely deal with change in the address book [part 2]

Summary:
7a2ecf16df938dd95d3130a46082def7a02338eb Wallet: Change IsMine check in CWallet::DelAddressBook from assert to failure (Luke Dashjr)
2952c46b923042f2de801f319e03ed5c4c4eb735 Wallet: Replace CAddressBookData.name with GetLabel() method (Luke Dashjr)
d7092c392e10889cd7a080b3d22ed6446a59b87a QA: Test that change doesn't turn into non-change when spent in an avoid-reuse wallet (Luke Dashjr)

Pull request description:

Follow-up to #18192, not strictly necessary for 0.20

Depends on D7810 and introduces tests for it too

Backport of Core PR18546

Test Plan: ninja check check-functional

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D7811