Qt: Fix race condition when switching to fullscreen

Stops the window opening in the corner of the screen occasionally in Wayland.

src/duckstation-qt/mainwindow.cpp

@@ -160,6 +160,8 @@ QtDisplayWidget* MainWindow::createDisplay(QThread* worker_thread, bool fullscre
   // we need the surface visible.. this might be able to be replaced with something else
   QCoreApplication::processEvents(QEventLoop::ExcludeUserInputEvents);
 
+  m_host_interface->connectDisplaySignals(m_display_widget);
+
   std::optional<WindowInfo> wi = m_display_widget->getWindowInfo();
   if (!wi.has_value())
   {
@@ -262,6 +264,8 @@ QtDisplayWidget* MainWindow::updateDisplay(QThread* worker_thread, bool fullscre
   // we need the surface visible.. this might be able to be replaced with something else
   QCoreApplication::processEvents(QEventLoop::ExcludeUserInputEvents);
 
+  m_host_interface->connectDisplaySignals(m_display_widget);
+
   std::optional<WindowInfo> wi = m_display_widget->getWindowInfo();
   if (!wi.has_value())
   {

src/duckstation-qt/qthostinterface.cpp

@@ -578,7 +578,6 @@ bool QtHostInterface::AcquireHostDisplay()
     return false;
   }
 
-  connectDisplaySignals(display_widget);
   m_is_exclusive_fullscreen = m_display->IsFullscreen();
   return true;
 }
@@ -641,7 +640,6 @@ void QtHostInterface::updateDisplayState()
   if (!display_widget || !m_display->MakeRenderContextCurrent())
     Panic("Failed to make device context current after updating");
 
-  connectDisplaySignals(display_widget);
   m_is_exclusive_fullscreen = m_display->IsFullscreen();
 
   OnHostDisplayResized();

src/duckstation-qt/qthostinterface.h

@@ -90,6 +90,7 @@ public:
   ALWAYS_INLINE MainWindow* getMainWindow() const { return m_main_window; }
   void setMainWindow(MainWindow* window);
   HostDisplay* createHostDisplay();
+  void connectDisplaySignals(QtDisplayWidget* widget);
 
   void populateLoadStateMenu(const char* game_code, QMenu* menu);
   void populateSaveStateMenu(const char* game_code, QMenu* menu);
@@ -269,7 +270,6 @@ private:
   void shutdownOnThread();
   void installTranslator();
   void renderDisplay();
-  void connectDisplaySignals(QtDisplayWidget* widget);
   void checkRenderToMainState();
   void updateDisplayState();
   void queueSettingsSave();