Get rid of the sprite on buttons until I have a better idea about the overall design.

combat_ui.cpp

@@ -24,7 +24,7 @@ namespace gui {
       if(name.starts_with("button_")) {
         auto button = $gui.entity(name);
         world.set<lel::Cell>(button, cell);
-        world.set<Sprite>(button, {"trash_button"});
+        world.set<Rectangle>(button, {});
         world.set<Clickable>(button,
             guecs::make_action(*$level.world, Events::GUI::ATTACK));
         world.set<Label>(button, {"Attack"});