enable full linter across the codebase (#9620)

enable linter using golangci-lint across
codebase to run a bunch of linters together,
we shall enable new linters as we fix more
things the codebase.

This PR fixes the first stage of this
cleanup.

cmd/metrics-router.go

@@ -48,6 +48,8 @@ func registerMetricsRouter(router *mux.Router) {
 	switch prometheusAuthType(authType) {
 	case prometheusPublic:
 		metricsRouter.Handle(prometheusMetricsPath, metricsHandler())
+	case prometheusJWT:
+		fallthrough
 	default:
 		metricsRouter.Handle(prometheusMetricsPath, AuthMiddleware(metricsHandler()))
 	}