Remove CGC from data_availability checker (#7033)

- Part of https://github.com/sigp/lighthouse/issues/6767

Validator custody makes the CGC and set of sampling columns dynamic. Right now this information is stored twice:
- in the data availability checker
- in the network globals

If that state becomes dynamic we must make sure it is in sync updating it twice, or guarding it behind a mutex. However, I noted that we don't really have to keep the CGC inside the data availability checker. All consumers can actually read it from the network globals, and we can update `make_available` to read the expected count of data columns from the block.

beacon_node/http_api/src/publish_blocks.rs

@@ -137,7 +137,8 @@ pub async fn publish_block<T: BeaconChainTypes, B: IntoGossipVerifiedBlock<T>>(
         spawn_build_data_sidecar_task(chain.clone(), block.clone(), unverified_blobs)?;
 
     // Gossip verify the block and blobs/data columns separately.
-    let gossip_verified_block_result = unverified_block.into_gossip_verified_block(&chain);
+    let gossip_verified_block_result = unverified_block
+        .into_gossip_verified_block(&chain, network_globals.custody_columns_count() as usize);
     let block_root = block_root.unwrap_or_else(|| {
         gossip_verified_block_result.as_ref().map_or_else(
             |_| block.canonical_root(),