Flutter_webview_plugin, into Webview Website Google and Facebook login not working

I am using Flutter_webview_plugin to open a website like Godaddy or another, where is the have a login access button with Google and Facebook and I try to login or signup with Google or Facebook then it's not working.

firstly I was getting userAgent issue but I have added userAgent so now when i have gone for login using google or Facebook, then it take permissions after the permission it does not redirect on web URL and also it's not LoggedIn.

I am using this so please check and help me.

```
`Future makemytrip(BuildContext context) async {
var makemytripUrl = Container(

padding: const EdgeInsets.only(top: 25.0),

decoration: BoxDecoration(color: Colors.white),

child: WebviewScaffold(url: "https://makemytrip.com/",

userAgent:"Mozilla/5.0 (Linux; Android 4.1.1; Galaxy Nexus Build/JRO03C) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.166 Mobile Safari/535.19",

withJavascript: true,

),

);

await Navigator.push(

context,

MaterialPageRoute(builder: (context) => makemytripUrl),

);

}`
```

从 issue 中展示的 WebviewScaffold 配置开始，包括 userAgent 和 withJavascript，并针对列出的 makemytrip.com URL 复现 Google 和 Facebook 登录流程。当权限流程重定向回网站并使用户保持登录状态，或记录 plugin 的限制时，即视为完成。

由索引模型根据 Issue 内容生成。