fix LC header production for Deneb (#5763)

The `blob_gas_used` field was not properly populated when constructing
Deneb light client data. This is due to #5026 not applying the change to
the entire codebase when the new field got introduced, and due to #5350
not catching that oversight in other modules. Also reviewed codebase and
discovered that `shortLog` for Deneb execution payloads has same bug.

beacon_chain/spec/datatypes/deneb.nim

@@ -585,6 +585,7 @@ func shortLog*(v: ExecutionPayload): auto =
     block_hash: shortLog(v.block_hash),
     num_transactions: len(v.transactions),
     num_withdrawals: len(v.withdrawals),
+    blob_gas_used: $(v.blob_gas_used),
     excess_blob_gas: $(v.excess_blob_gas)
   )
 

beacon_chain/spec/forks_light_client.nim

@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2023 Status Research & Development GmbH
+# Copyright (c) 2023-2024 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -946,6 +946,7 @@ func toDenebLightClientHeader(
       block_hash: payload.block_hash,
       transactions_root: hash_tree_root(payload.transactions),
       withdrawals_root: hash_tree_root(payload.withdrawals),
+      blob_gas_used: payload.blob_gas_used,
       excess_blob_gas: payload.excess_blob_gas),
     execution_branch: blck.message.body.build_proof(
       capella.EXECUTION_PAYLOAD_GINDEX).get)