[avalanche] Remote proofs: account for our local proof if we are a staker

Summary:
I we are staking, we are taking part of the decision about a proof so it makes sense to weight also on the remote proof decision, proportionally to our stake.

Depends on D14961.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D14962