I've been struggling with an authentication issue and would really appreciate any advice or suggestions from people who may have done it before. We are developing a web resource which is primarily intended for use on the Dynamics 365 Android app. We are hoping to add SharePoint document upload straight from the web resource to allow our technicians to add photos of assets without navigating away. The issue I am having is that although I am able to obtain the OAuth and access tokens on the web interface (via msal.js), these methods don't work on the mobile app due to the fact that popups and redirects are disabled. What options do I have for obtaining an access token that will allow me to use either the SharePoint REST API or MS Graph API without redirection or popups?