unable to set up SAML SSO with Entra ID

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

1. Create an MS Entra ID (former Azure) organisation
2. Add Entra ID user to a secure group
4. Try to configure SSO following the steps on this page https://docs.sentry.io/organization/authentication/sso/azure-sso/

### Expected Result

SSO is configured.

### Actual Result

SSO is not configured and no error is shown.

The no error showing in the [UI is a result of this known issue](https://github.com/getsentry/sentry/issues/96631), which is blocking the troubleshooting of the affected user.

What have been done so far:
- Confirmed all attributes set in Sentry are sent in the SAMLResponse
- The attributes are valid and match an existing user in Sentry. The email address has dots and capitals, when reproducing the same email it worked on a test organisation.
- Confirmed additional claims do not affect result.

Full information is available in the internal Linear ticket.

### Product Area

Settings - Auth

### Link

_No response_

### DSN

_No response_

### Version

_No response_

Start with the SSO setup instructions at docs.sentry.io/organization/authentication/sso/azure-sso/ and review the linked issue #96631 about missing UI errors. Compare the reported Entra ID SAML configuration and claims with the working test organisation; done means identifying why setup fails and providing a visible, actionable error or a confirmed configuration fix.

Written by the indexing model from the issue text.