[common]: fix potential leak on Sleep.

internal/common/sleep.go

@@ -11,6 +11,9 @@ func Sleep(ctx context.Context, interval time.Duration) error {
 	timer := time.NewTimer(interval)
 	select {
 	case <-ctx.Done():
+		if !timer.Stop() {
+			<-timer.C
+		}
 		return ctx.Err()
 	case <-timer.C:
 		return nil