How to request Microsoft Graph scope or any other custom scope using office API `Office.auth.getAccessToken()` in an Outlook Add-In?

Question

I am developing a React.js-based Outlook add-in and using the Office.auth.getAccessToken() API to authenticate users. But I need to obtain an access token A with additional Microsoft Graph API scopes (e.g., Mail.Read, User.Read).

From my research, I understand that:

• Office.auth.getAccessToken() provides an identity token (Token A) but does not allow specifying custom Graph API scopes.
• The WebApplicationInfo section in the Outlook add-in manifest does not support defining additional Microsoft Graph permissions.
• The recommended approach is to use MSAL.js separately to acquire a token (Token B) with the required Graph API scopes.

Question:

Is there any way to configure the WebApplicationInfo element or any other method to obtain Token A with Graph API scope or any other custom scope directly using Office.auth.getAccessToken()?