User Identity - Temporary Patch to Prevent Duplicate Account Creation

[JoseSzycho]

High-Level Summary

Implement a temporary patch to block the creation of new user accounts when another account with the same email address already exists. This is intended as a stopgap measure until a more robust identity management solution is in place.

Motivation

Currently, it is possible for multiple user accounts to be created with the same email address, leading to confusion, security risks, and data integrity issues. This patch will prevent further duplicate accounts from being created, reducing operational overhead and user friction.

Goals

• Prevent creation of new Milo accounts if an account with the same email address already exists.
• Ensure the patch is easy to revert or replace with a permanent solution.
• Minimize impact on existing authentication and registration flows.

Non-Goals

• This is not a permanent solution for account deduplication.
• Does not merge or link existing duplicate accounts.
• Does not address broader identity consolidation or federation issues.