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>

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -1602,7 +1602,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 // This method is called for API and gossip attestations, so this covers all unaggregated attestation events
                 if let Some(event_handler) = self.event_handler.as_ref() {
                     if event_handler.has_attestation_subscribers() {
-                        event_handler.register(EventKind::Attestation(v.attestation().clone()));
+                        event_handler
+                            .register(EventKind::Attestation(Box::new(v.attestation().clone())));
                     }
                 }
                 metrics::inc_counter(&metrics::UNAGGREGATED_ATTESTATION_PROCESSING_SUCCESSES);
@@ -1638,7 +1639,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             // This method is called for API and gossip attestations, so this covers all aggregated attestation events
             if let Some(event_handler) = self.event_handler.as_ref() {
                 if event_handler.has_attestation_subscribers() {
-                    event_handler.register(EventKind::Attestation(v.attestation().clone()));
+                    event_handler
+                        .register(EventKind::Attestation(Box::new(v.attestation().clone())));
                 }
             }
             metrics::inc_counter(&metrics::AGGREGATED_ATTESTATION_PROCESSING_SUCCESSES);