feat: ensure attestation source slot does not exceed target

[zemse]

What was wrong?

Ream already uses source from the head chain for voting. But we are missing:

1. source.slot <= target.slot sanity guard in produce_attestation_data
2. running the new consensus vector

Closes #1448.

How was it fixed?

• sanity guard added in produce_attestation_data
• per-validator attestation checks in validate_checks
• existing run_attestation_pipeline validation replaced with store.on_gossip_attestation because validate_checks depend on voting state recorded in attestation_signatures.
• is_aggregator is added to ForkChoiceStep::Attestation type which is used in the test vector
• validator_id is set to 0 to enable the store to become aggregator
• enable devnet5 fork_choice suite filtered to test_honest_vote_sources_from_head_chain_not_store vector introduced in lean spec upstream.

Click to see screenshot of tests

Devnet 5 test vector passing:

Devnet 4 tests remain unaffected:

To-Do

• I have read CONTRIBUTING.md.
• This PR title follows conventional commits.

[KolbyML]

can you rebase this