remove unneeded includes when building without BIP70

Summary:
This is a follow-up to D15407
These changes enable building Qt with -no-feature-networkproxy when BIP70 is disabled

Depends on D15427

Test Plan:

cmake .. -GNinja -DENABLE_BIP70=OFF
ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D15428