Import gossip data column into data availability checker (#6197)

* Import gossip data column into data availability checker

beacon_node/beacon_chain/src/early_attester_cache.rs

@@ -22,6 +22,7 @@ pub struct CacheItem<E: EthSpec> {
      */
     block: Arc<SignedBeaconBlock<E>>,
     blobs: Option<BlobSidecarList<E>>,
+    data_columns: Option<DataColumnSidecarList<E>>,
     proto_block: ProtoBlock,
 }
 
@@ -69,7 +70,7 @@ impl<E: EthSpec> EarlyAttesterCache<E> {
             },
         };
 
-        let (_, block, blobs) = block.deconstruct();
+        let (_, block, blobs, data_columns) = block.deconstruct();
         let item = CacheItem {
             epoch,
             committee_lengths,
@@ -78,6 +79,7 @@ impl<E: EthSpec> EarlyAttesterCache<E> {
             target,
             block,
             blobs,
+            data_columns,
             proto_block,
         };
 
@@ -164,6 +166,15 @@ impl<E: EthSpec> EarlyAttesterCache<E> {
             .and_then(|item| item.blobs.clone())
     }
 
+    /// Returns the data columns, if `block_root` matches the cached item.
+    pub fn get_data_columns(&self, block_root: Hash256) -> Option<DataColumnSidecarList<E>> {
+        self.item
+            .read()
+            .as_ref()
+            .filter(|item| item.beacon_block_root == block_root)
+            .and_then(|item| item.data_columns.clone())
+    }
+
     /// Returns the proto-array block, if `block_root` matches the cached item.
     pub fn get_proto_block(&self, block_root: Hash256) -> Option<ProtoBlock> {
         self.item