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>

consensus/state_processing/src/upgrade.rs

@@ -1,9 +1,7 @@
 pub mod altair;
 pub mod capella;
-pub mod eip4844;
 pub mod merge;
 
 pub use altair::upgrade_to_altair;
 pub use capella::upgrade_to_capella;
-pub use eip4844::upgrade_to_eip4844;
 pub use merge::upgrade_to_bellatrix;