Publish a signed block.
Instructs the beacon node to use the components of the SignedBlindedBeaconBlock to construct and publish a
SignedBeaconBlock by swapping out the transactions_root for the corresponding full list of transactions.
The beacon node should broadcast a newly constructed SignedBeaconBlock to the beacon network,
to be included in the beacon chain. The beacon node is not required to validate the signed
BeaconBlock, and a successful response (20X) only indicates that the broadcast has been
successful. The beacon node is expected to integrate the new block into its state, and
therefore validate the block internally, however blocks which fail the validation are still
broadcast but a different status code is returned (202). Before Bellatrix, this endpoint will accept
a SignedBeaconBlock. The broadcast behaviour may be adjusted via the broadcast_validation
query parameter.