Proto: update dal_entrapment_evidence to cover attestations aggregate

What

Update the Dal_entrapment_evidence to be able to cover aggregates.

Corresponding DAL-node update: !18057 (merged)

How

• Generalize the attestation field to any kind consensus operation
• Add a new consensus_slot field

With the following semantics:

• If attestation is a standalone attestation, consensus_slot must be its slot.
• If attestation is an attestations aggregate, its committee must include consensus_slot and the denunciation targets consensus_slot's DAL content.
• If attestation is a preattestation or preattestations aggregate, the dal entrapment evidence is invalid.

Note that allowing preattestations in the encoding (even if it results in an invalid operation) is more general than necessary for Dal_entrapment_evidence. However, the same code will be reused to generalize denunciations of double consensus operations to also cover aggregates.