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.
},
...
}
```

Commencez par ms-identity-ciam-javascript-tutorial\1-Authentication\0-sign-in-vanillajs\App\public\authConfig.js et reproduisez le flux de connexion avec chaque URL d’autorité indiquée dans l’issue. Comparez le comportement obtenu et confirmez le format d’autorité attendu pour cette configuration du tutoriel.

Rédigé par le modèle d'indexation à partir du texte de l'issue.