Auth - Support for Azure AD OBO (On Behalf Of) OAuth Token Integration

### Problem Statement Our team is integrating Azure with Sentry, but due to security policies, we are unable to use standard OAuth authentication. Instead, we are leveraging the On Behalf Of (OBO) OAuth token flow provided by Azure AD to authenticate users and access resources. However, Sentry currently does not support this flow natively, requiring custom workarounds on our side. We are requesting native support for the Azure OBO flow to enable smoother integration between Azure AD and Sentry. ### Solution Brainstorm _No response_ ### Product Area Settings - Integrations ┆Issue is synchronized with this [Jira Improvement](https://getsentry.atlassian.net/browse/FEEDBACK-2325) by [Unito](https://www.unito.io)