1.57.0 lints (#2850)

## Issue Addressed

New rust lints

## Proposed Changes

- Boxing some enum variants
- removing some unused fields (is the validator lockfile unused? seemed so to me)

## Additional Info

- some error fields were marked as dead code but are logged out in areas
- left some dead fields in our ef test code because I assume they are useful for debugging?

Co-authored-by: realbigsean <seananderson33@gmail.com>

validator_client/src/config.rs

@@ -131,7 +131,7 @@ impl Config {
         if let Some(beacon_nodes) = parse_optional::<String>(cli_args, "beacon-nodes")? {
             config.beacon_nodes = beacon_nodes
                 .split(',')
-                .map(|s| SensitiveUrl::parse(s))
+                .map(SensitiveUrl::parse)
                 .collect::<Result<_, _>>()
                 .map_err(|e| format!("Unable to parse beacon node URL: {:?}", e))?;
         }