apollo_consensus: check for duplicate votes before caching

[guy-starkware]

Note

Medium Risk
Touches consensus network message handling and changes how future votes are cached/reported, which could affect peer reporting behavior and cache contents under real network conditions.

Overview
Adds duplicate detection when caching future-height votes: ConsensusCache::cache_future_vote now de-duplicates by (vote_type, round, voter), silently ignoring identical repeats while returning a DuplicateVoteReport for conflicting votes.

MultiHeightManager::handle_vote uses this report to log a warning and report_peer on equivocation attempts, and a new test cache_future_vote_deduplication asserts that identical duplicates do not trigger reporting while conflicting duplicates do.

^{Written by Cursor Bugbot for commit 3703184. This will update automatically on new commits. Configure here.}

[reviewable-StarkWare]

This change is 

[guy-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• apollo_network: pass the reBadPeerReport when reporting #12474
• apollo_network: struct that holds the reason the peer is considered bad #12470
• apollo_network: add BadPeerReport and PenaltyCard #12463
• apollo_consensus: check for duplicate votes before caching #12465 👈 (View in Graphite)
• apollo_consensus: add helper function to report peer #12464
• main-v0.14.1-committer

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