Fix missing mockAPI import in CartContent component

- Add missing import for mockAPI from utils/mockData
- Resolves ESLint error: 'mockAPI' is not defined no-undef
- Fix production build failure on GitHub Actions
- All components now build successfully

Author: dawidolko

frontend/src/components/CartContent/CartContent.jsx

@@ -55,6 +55,7 @@ import { useNavigate } from "react-router-dom";
 import { toast } from "react-toastify";
 import config from "../../config/config";
 import DemoFallback from "../DemoFallback/DemoFallback";
+import { mockAPI } from "../../utils/mockData";
 
 const CartContent = () => {
   const { items, totalAmount, removeFromCart, addToCart } =