Qt: Fall back to screen for refresh rate

Wayland, always a pain in the arse.

src/duckstation-qt/qtutils.cpp

@@ -370,7 +370,17 @@ std::optional<WindowInfo> GetWindowInfoForWidget(QWidget* widget)
   wi.surface_scale = static_cast<float>(dpr);
 
   // Query refresh rate, we need it for sync.
-  wi.surface_refresh_rate = WindowInfo::QueryRefreshRateForWindow(wi).value_or(0.0f);
+  std::optional<float> surface_refresh_rate = WindowInfo::QueryRefreshRateForWindow(wi);
+  if (!surface_refresh_rate.has_value())
+  {
+    // Fallback to using the screen, getting the rate for Wayland is an utter mess otherwise.
+    const QScreen* widget_screen = widget->screen();
+    if (!widget_screen)
+      widget_screen = QGuiApplication::primaryScreen();
+    surface_refresh_rate = widget_screen ? static_cast<float>(widget_screen->refreshRate()) : 0.0f;
+  }
+
+  wi.surface_refresh_rate = surface_refresh_rate.value();
   INFO_LOG("Surface refresh rate: {} hz", wi.surface_refresh_rate);
 
   return wi;