refactor: change pointer parameters to references for Level and Content in various classes

src/frontend/screens/LevelScreen.cpp

@@ -92,8 +92,8 @@ LevelScreen::LevelScreen(Engine& engine, std::unique_ptr<Level> levelPtr)
 }
 
 void LevelScreen::initializeContent() {
-    auto content = controller->getLevel()->content;
-    for (auto& entry : content->getPacks()) {
+    auto& content = controller->getLevel()->content;
+    for (auto& entry : content.getPacks()) {
         initializePack(entry.second.get());
     }
     scripting::on_frontend_init(hud.get(), worldRenderer.get());