[avalanche] Manage the notfound messages from a proof request

Summary:
Handle the case of peer sending a notfound in response of a proof
request. We should then select another peer for the download.

Depends on D9582.

Test Plan:

ninja all check
./test/functional/test_runner.py p2p_inv_download

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Subscribers: deadalnix

Maniphest Tasks: T1611

Differential Revision: https://reviews.bitcoinabc.org/D9599