[avalanche] Fix the inboud requesting functional test

Summary: The test is using a data structure that has been removed before it was landed, and sliped through the rebase as it created no conflicts.

Test Plan:

./test/functional/test_runner.py abc_p2p_compactproofs

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D11754