Merge remote-tracking branch 'origin/unstable' into capella

Fixing the conflicts involved patching up some of the `block_hash` verification,
the rest will be done as part of https://github.com/sigp/lighthouse/issues/3870

beacon_node/client/src/builder.rs

@@ -174,6 +174,7 @@ where
             .monitor_validators(
                 config.validator_monitor_auto,
                 config.validator_monitor_pubkeys.clone(),
+                config.validator_monitor_individual_tracking_threshold,
                 runtime_context
                     .service_context("val_mon".to_string())
                     .log()