get https://{network-ethereum}.gateway.tatum.io/eth/v2/validator/aggregate_attestation
Aggregates all attestations matching given attestation data root, slot and committee index.
A 503 error must be returned if the block identified by the response
beacon_block_root is optimistic (i.e. the aggregated attestation attests
to a block that has not been fully verified by an execution engine).
A 404 error must be returned if no attestation is available for the requested
attestation_data_root.