[avalanche] Send getavaproofs periodically to one random peer

Summary:
The getavaproofs requests are only requested upon connection for now, let send more on a regular basis. This will help keeping up to date even if we don't connect to new peers.

Depends on D11612.

Test Plan:

./test/functional/test_runner.py abc_p2p_compactproofs

Reviewers: #bitcoin_abc, sdulfari

Reviewed By: #bitcoin_abc, sdulfari

Subscribers: sdulfari

Differential Revision: https://reviews.bitcoinabc.org/D11613