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/network/src/sync/backfill_sync/mod.rs

@@ -148,7 +148,6 @@ pub struct BackFillSync<T: BeaconChainTypes> {
 
 impl<T: BeaconChainTypes> BackFillSync<T> {
     #[instrument(parent = None,
-        level = "info",
         name = "backfill_sync",
         skip_all
     )]