[net processing] Change AlreadyHaveTx() to take a GenTxid
Summary:
Partial backport if core#19610:
https://github.com/bitcoin/bitcoin/pull/19610/commits/acd66421671e42a58e8e067868e1ab86268e3231
Depends on D9504.
Test Plan:
ninja all check-all
Reviewers: #bitcoin_abc, majcosta
Reviewed By: #bitcoin_abc, majcosta
Differential Revision: https://reviews.bitcoinabc.org/D9505