Remove KZG verification on blobs fetched from the EL (#7771)

Continuation of #7713, addresses comment about skipping KZG verification on EL fetched blobs:

https://github.com/sigp/lighthouse/pull/7713#discussion_r2198542501

beacon_node/beacon_chain/src/data_availability_checker.rs

@@ -1,4 +1,6 @@
-use crate::blob_verification::{verify_kzg_for_blob_list, GossipVerifiedBlob, KzgVerifiedBlobList};
+use crate::blob_verification::{
+    verify_kzg_for_blob_list, GossipVerifiedBlob, KzgVerifiedBlob, KzgVerifiedBlobList,
+};
 use crate::block_verification_types::{
     AvailabilityPendingExecutedBlock, AvailableExecutedBlock, RpcBlock,
 };
@@ -264,6 +266,15 @@ impl<T: BeaconChainTypes> DataAvailabilityChecker<T> {
             .put_kzg_verified_blobs(block_root, blobs.into_iter().map(|b| b.into_inner()))
     }
 
+    pub fn put_kzg_verified_blobs<I: IntoIterator<Item = KzgVerifiedBlob<T::EthSpec>>>(
+        &self,
+        block_root: Hash256,
+        blobs: I,
+    ) -> Result<Availability<T::EthSpec>, AvailabilityCheckError> {
+        self.availability_cache
+            .put_kzg_verified_blobs(block_root, blobs)
+    }
+
     /// Check if we've cached other data columns for this block. If it satisfies the custody requirement and we also
     /// have a block cached, return the `Availability` variant triggering block import.
     /// Otherwise cache the data column sidecar.