Prevent scheduler's healtcheck FAIL when disabled

pkg/scheduler/healthcheck.go

@@ -8,7 +8,7 @@ import (
 // Healtcheck for (global) scheduler
 func Healthcheck(ctx context.Context) error {
 	if gScheduler == nil {
-		return fmt.Errorf("uninitialized")
+		return nil
 	}
 
 	if gScheduler.ticker == nil {