Aap-controller: aap-gateway: account hijacking and unauthorized access via unverified email linking

A flaw was found in the AAP gateway. The user auto-link strategy, introduced in AAP 2.6, automatically links an external Identity Provider (IDP) identity to an existing AAP user account based on email matching without verifying email ownership. This allows a remote attacker to potentially hijack a victim's account or gain unauthorized access to other accounts, including administrative accounts, by manipulating the IDP-provided email.