[avalanche] Deduplicate the getavaproofs response test

Summary: The removal from abc_p2p_proof_inventory has been lost in D11533, duplicating the test instead of moving it.

Test Plan:

./test/functional/test_runner.py abc_p2p_proof_inventory

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D11652