Clean capella (#4019)

## Issue Addressed

Cleans up all the remnants of 4844 in capella. This makes sure when 4844 is reviewed there is nothing we are missing because it got included here 

## Proposed Changes

drop a bomb on every 4844 thing 

## Additional Info

Merge process I did (locally) is as follows:
- squash merge to produce one commit
- in new branch off unstable with the squashed commit create a `git revert HEAD` commit
- merge that new branch onto 4844 with `--strategy ours`
- compare local 4844 to remote 4844 and make sure the diff is empty
- enjoy

Co-authored-by: Paul Hauner <paul@paulhauner.com>

beacon_node/lighthouse_network/src/config.rs

@@ -305,9 +305,7 @@ pub fn gossipsub_config(network_load: u8, fork_context: Arc<ForkContext>) -> Gos
     ) -> Vec<u8> {
         let topic_bytes = message.topic.as_str().as_bytes();
         match fork_context.current_fork() {
-            // according to: https://github.com/ethereum/consensus-specs/blob/dev/specs/merge/p2p-interface.md#the-gossip-domain-gossipsub
-            // the derivation of the message-id remains the same in the merge and for eip 4844.
-            ForkName::Altair | ForkName::Merge | ForkName::Capella | ForkName::Eip4844 => {
+            ForkName::Altair | ForkName::Merge | ForkName::Capella => {
                 let topic_len_bytes = topic_bytes.len().to_le_bytes();
                 let mut vec = Vec::with_capacity(
                     prefix.len() + topic_len_bytes.len() + topic_bytes.len() + message.data.len(),