chore: add explict context cancellation for testing

Author: blockchainluffy

rolling-shutter/keyperimpl/shutterservice/syncmonitor.go

@@ -25,6 +25,11 @@ func (s *SyncMonitor) Start(ctx context.Context, runner service.Runner) error {
 		return s.runMonitor(ctx)
 	})
 
+	runner.Go(func() error {
+		<-time.After(30 * time.Minute)
+		return errors.New("explicitly canceling context")
+	})
+
 	return nil
 }