[backport#15288] Remove use of CalculateMemPoolAncestors in wallet code

Summary:
1fb0a4a04e9cda19ed5ad04694a39c83c91b6072 This commit does not change behavior. (Russell Yanofski)

Depends on D5826

This is a partial backport of Core PR15288

Test Plan:

cmake .. -DENABLE_WERROR=ON -DCMAKE_BUILD_TYPE=Debug
ninja check check-functional

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Subscribers: deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D5831