Remove instrumenting log level (#7620)

I think this should resolve #7155


This removes the level field from the instrumenting we were doing across a range of functions. The level will now default to the level of the log.

beacon_node/beacon_chain/src/validator_monitor.rs

@@ -406,7 +406,6 @@ pub struct ValidatorMonitor<E: EthSpec> {
 
 impl<E: EthSpec> ValidatorMonitor<E> {
     #[instrument(parent = None,
-        level = "info",
         name = "validator_monitor",
         skip_all
     )]