UiService v2.1: Virtualized lists (#2342)

* UiService: Add `pane_add_list`

* Fix CSS scoping

src/dusk/ui/achievements.cpp

@@ -185,8 +185,6 @@ AchievementsWindow::AchievementsWindow() {
                 *confirmingAll = false;
                 clearAllPtr->set_text("Clear All Achievements");
             });
-
-            pane.finalize();
         });
     }
 }