[CMAKE] Fix Qt tests when the wallet is not built

Summary:
This diff makes the addressbooktests.cpp to only build when the wallet
is enabled.

Test Plan:

cmake -GNinja .. -DBUILD_BITCOIN_WALLET=OFF
ninja check

Reviewers: #bitcoin_abc, deadalnix, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Differential Revision: https://reviews.bitcoinabc.org/D4719