Support changing users emails and name via SCIM

### Problem Statement

Currently, it is not possible for our SCIM integration to change Sentry users' names and email addresses. It is only possible to add/remove users from the organisation, change roles and team assignment (via Okta SCIM).

But changing users' information is not currently supported.

### Solution Brainstorm

This being a common feature in user management and provisioning, administrators expect to be able to change users' names and email addresses in the IdP and have these changes reflected in the Sentry users.

This is a request to add support for it.

### Product Area

Settings - Auth

Start by reading the SCIM integration and its existing Okta provisioning behavior, focusing on how users are currently added, removed, assigned roles, and assigned to teams. Determine the expected handling for IdP-driven name and email changes, then verify that those updates are reflected in Sentry users without changing the existing provisioning behavior.

Written by the indexing model from the issue text.