add go linter - "unused" (#11235)

* add go linter - "unused"

* use _ to name unused but needed padding variable

* remove unused code

* add queue test to appease unused linter

* remove unused code in test

* remove unused func

* remove unused struct identified by linter

* remove unused variable

* remove unused code

* remove unused file

* remove unused struct

* remove unused function

* remove unused observe peers function in raft

* remove unused declareFaults function

* annotate nolint:unused on needed methods

node/modules/actorevent.go

@@ -126,8 +126,6 @@ func EthEventAPI(cfg config.FevmConfig) func(helpers.MetricsCtx, repo.LockedRepo
 			MaxFilterResults: cfg.Events.MaxFilterResults,
 		}
 
-		const ChainHeadConfidence = 1
-
 		lc.Append(fx.Hook{
 			OnStart: func(context.Context) error {
 				ev, err := events.NewEvents(ctx, &evapi)