Prepares the beacon node for engaging with external builders. The
information will be sent by the beacon node to the builder network. It is
expected that the validator client will send this information periodically
to ensure the beacon node has correct and timely registration information
to provide to builders. The validator client should not sign blinded beacon
blocks that do not adhere to their latest fee recipient and gas limit
Note that requests containing currently inactive or unknown validator
pubkeys will be accepted, as they may become active at a later epoch.