[avalanche] Move the invalid proofs filter to the peer manager

Summary:
This is actually a global in net_processing, move it to the peer manager where it belongs and gives accessors.
This will make it possible to declare a proof invalid from a RPC (future diff).

There is no change of behavior.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Subscribers: PiRK

Differential Revision: https://reviews.bitcoinabc.org/D14734