Common: Make HookableEvent use non-static data.

Co-authored-by: Dentomologist <[email protected]>

Source/Core/DolphinQt/Achievements/AchievementsWindow.cpp

@@ -31,7 +31,7 @@ AchievementsWindow::AchievementsWindow(QWidget* parent) : QDialog(parent)
   CreateMainLayout();
   ConnectWidgets();
 
-  m_event_hook = AchievementManager::UpdateEvent::Register(
+  m_event_hook = AchievementManager::GetInstance().update_event.Register(
       [this](AchievementManager::UpdatedItems updated_items) {
         QueueOnObject(this, [this, updated_items = std::move(updated_items)] {
           AchievementsWindow::UpdateData(std::move(updated_items));