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>

lcli/src/main.rs

@@ -425,7 +425,7 @@ fn main() {
                     .takes_value(true)
                     .default_value("bellatrix")
                     .help("The fork for which the execution payload header should be created.")
-                    .possible_values(&["merge", "bellatrix", "capella", "eip4844"])
+                    .possible_values(&["merge", "bellatrix", "capella"])
             )
         )
         .subcommand(