Implement PeerDAS Fulu fork activation (#6795)

Addresses #6706


  This PR activates PeerDAS at the Fulu fork epoch instead of `EIP_7594_FORK_EPOCH`. This means we no longer support testing PeerDAS with Deneb / Electrs, as it's now part of a hard fork.

beacon_node/beacon_chain/src/errors.rs

@@ -226,6 +226,10 @@ pub enum BeaconChainError {
     EmptyRpcCustodyColumns,
     AttestationError(AttestationError),
     AttestationCommitteeIndexNotSet,
+    InsufficientColumnsToReconstructBlobs {
+        columns_found: usize,
+    },
+    FailedToReconstructBlobs(String),
 }
 
 easy_from_to!(SlotProcessingError, BeaconChainError);