Removed FOCUS-51062 - Respect Forbidden Domains when Changing Parent Email

Enhanced the System Preference Sync Parent Username and Email Address to enforce restrictions for forbidden or disallowed email domains at the time of update. When this preference is enabled, any parent attempting to register or update their email to a domain listed in Prevent parent accounts with domain @ will now receive an error message and be prevented from saving the change. This ensures consistent enforcement of domain restrictions both during account creation and profile updates in the Parent Portal.