msalConfig auth authority URL

It is not working if the authority URL in `authConfig.js` (`ms-identity-ciam-javascript-tutorial\1-Authentication\0-sign-in-vanillajs\App\public\authConfig.js`) is `https://.ciamlogin.com/`, but it works with `https://.ciamlogin.com//v2.0`

```js
const msalConfig = {
auth: {
clientId: 'Enter_the_Application_Id_Here', // This is the ONLY mandatory field that you need to supply.
authority: 'https://Enter_the_Tenant_Subdomain_Here.ciamlogin.com/Enter_the_Tenant_Subdomain_Here/v2.0', // Replace the placeholders with your tenant subdomain
redirectUri: 'http://localhost:3000/redirect', // You must register this URI on Microsoft Entra admin center/App Registration. Defaults to window.location.href e.g. http://localhost:3000/
navigateToLoginRequestUrl: true, // If "true", will navigate back to the original request location before processing the auth code response.
},
...
}
```

从 ms-identity-ciam-javascript-tutorial\1-Authentication\0-sign-in-vanillajs\App\public\authConfig.js 开始，使用 issue 中显示的每个 authority URL 重现登录流程。比较产生的行为，并确认此教程配置所需的 authority 格式。

由索引模型根据 Issue 内容生成。