Deneb pr updates 2 (#4851)

* use workspace deps in kzg crate

* delete unused blobs dp path field

* full match on fork name in engine api get payload v3

* only accept v3 payloads on get payload v3 endpoint in mock el

* remove FIXMEs related to merge transition tests

* move static tx to test utils

* default max_per_epoch_activation_churn_limit to mainnet value

* remove unnecessary async

* remove comment

* use task executor in `blob_sidecars` endpoint

beacon_node/client/src/builder.rs

@@ -71,7 +71,6 @@ pub struct ClientBuilder<T: BeaconChainTypes> {
     gossipsub_registry: Option<Registry>,
     db_path: Option<PathBuf>,
     freezer_db_path: Option<PathBuf>,
-    blobs_db_path: Option<PathBuf>,
     http_api_config: http_api::Config,
     http_metrics_config: http_metrics::Config,
     slasher: Option<Arc<Slasher<T::EthSpec>>>,
@@ -106,7 +105,6 @@ where
             gossipsub_registry: None,
             db_path: None,
             freezer_db_path: None,
-            blobs_db_path: None,
             http_api_config: <_>::default(),
             http_metrics_config: <_>::default(),
             slasher: None,
@@ -927,7 +925,6 @@ where
 
         self.db_path = Some(hot_path.into());
         self.freezer_db_path = Some(cold_path.into());
-        self.blobs_db_path = blobs_path.clone();
 
         let inner_spec = spec.clone();
         let deposit_contract_deploy_block = context