Fix/remove some Electra attestation todos

[realbigsean]

Issue Addressed

• Removed logging about deneb attestations at the fork, current plan across clients is to just ignore them, and the logging here causes confusion
• run a few tests for both electra and base attestation types
• Remove a few todo's about verifying logic is correct. All of these reside in consensus/types/src/beacon_block.rs and look like they're correct. Would appreciate additional confirmation from reviewers here.

[eserilev]

not the best person to comment on the beacon_chain changes, but the changes to attestation, attester_slashing and the TODO removals in beacon_block look fine to me

[ethDreamer]