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/tests/common.rs

@@ -26,19 +26,16 @@ pub fn fork_context(fork_name: ForkName) -> ForkContext {
     let altair_fork_epoch = Epoch::new(1);
     let merge_fork_epoch = Epoch::new(2);
     let capella_fork_epoch = Epoch::new(3);
-    let eip4844_fork_epoch = Epoch::new(4);
 
     chain_spec.altair_fork_epoch = Some(altair_fork_epoch);
     chain_spec.bellatrix_fork_epoch = Some(merge_fork_epoch);
     chain_spec.capella_fork_epoch = Some(capella_fork_epoch);
-    chain_spec.eip4844_fork_epoch = Some(eip4844_fork_epoch);
 
     let current_slot = match fork_name {
         ForkName::Base => Slot::new(0),
         ForkName::Altair => altair_fork_epoch.start_slot(E::slots_per_epoch()),
         ForkName::Merge => merge_fork_epoch.start_slot(E::slots_per_epoch()),
         ForkName::Capella => capella_fork_epoch.start_slot(E::slots_per_epoch()),
-        ForkName::Eip4844 => eip4844_fork_epoch.start_slot(E::slots_per_epoch()),
     };
     ForkContext::new::<E>(current_slot, Hash256::zero(), &chain_spec)
 }