🐛 Fix VITE_API_URL reference

frontend/src/components/Header.tsx

@@ -8,9 +8,7 @@ import { NavLink } from "react-router-dom";
 import { ReactComponent as Logo } from "../assets/brick.svg";
 import styles from "./Header.module.css";
 
-const ADMIN_URL = import.meta.env.VITE_API_URL
-  ? `${import.meta.env.VITE_API_URL}/admin`
-  : "http://localhost:8000/admin/";
+const ADMIN_URL = `${import.meta.env.VITE_API_URL}/admin`;
 
 const navLinkStyles = ({ isActive }: { isActive: boolean }) => (isActive ? "nav-link active" : "nav-link");