Do RGB correction only on Qt5

src/qt/qt_vulkanwindowrenderer.cpp

@@ -900,7 +900,11 @@ VulkanWindowRenderer::onBlit(int buf_idx, int x, int y, int w, int h)
         strcat(path, fn);
 
         QImage image = this->grab();
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+        image.save(path, "png");
+#else
         image.rgbSwapped().save(path, "png");
+#endif
         monitors[r_monitor_index].mon_screenshots--;
     }
     if (monitors[r_monitor_index].mon_screenshots_clipboard) {