perf(userfront): optimize login web loading

userfront/web/index.html

@@ -31,10 +31,6 @@
 
     <title>Baron 로그인</title>
     <link rel="manifest" href="manifest.json" />
-    <link
-      href="https://fonts.googleapis.com/icon?family=Material+Icons"
-      rel="stylesheet"
-    />
   </head>
   <body>
     <script src="flutter_bootstrap.js" async></script>