[Bug] Emails are being modified with +{suffix} when attendee & host emails overlap

[linear]

Description

When the attendee email and host email coincide or are too similar, the system automatically appends a suffix to the original email, resulting in modified addresses such as:

aa@aa.com → aa+cmhyhz55c00001tqjyxm9fj3v@aa.com  
attendee1@mail.com → attendee1+{generated_string}@mail.com

Customers expect the original email to be returned in the API response, not a modified version.

Example response showing unexpected behavior:

"userPrimaryEmail": "Attendee1+cmhyhz55c00001tqjyxm9fj3v@duda.com"

"responses.email": "aa+cmhyhz55c00001tqjyxm9fj3v@aa.com"

Expected Behavior

• API should return the original email provided by the user, without adding a suffix.
• Suffixing logic (used internally to prevent collisions) should not overwrite or replace the customer-facing email fields.

Acceptance Criteria

• Email fields in API responses match the exact email provided in the booking payload.
• Suffixing logic only affects internal identifiers and never user-visible fields.
• Booking creation, reminders, notifications, and app integrations continue functioning without regressions.

[linear]

CAL-6843