Merge pull request #27082 from iiiuhuy:fix_bug

displayOverlay doesn't disappear after timeout #27082

Fixes #26555

### Expected Behaviour
An overlay should be displayed atop an image and then disappear after `delayms` has timed out, but it doesn't. Also, `displayStatusBar` doesn't appear to set any text on the window.

### Actual Behaviour
The overlay appears but doesn't disappear unless a mouse move event happens on the image.

### Changes
- Fixed the issue with `displayOverlay` not disappearing after the timeout.

### Checklist
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV.
- [x] The PR is proposed to the proper branch.
- [x] There is a reference to the original bug report and related work.
- [ ] There is accuracy test, performance test, and test data in the opencv_extra repository, if applicable.
- [ ] The feature is well documented, and sample code can be built with the project CMake.

modules/highgui/src/window_QT.cpp

@@ -2949,6 +2949,7 @@ void DefaultViewPort::stopDisplayInfo()
 {
     timerDisplay->stop();
     drawInfo = false;
+    viewport()->update();
 }