Session and Waitlist updated_at Field Updates

Sessions

• Enhanced session endpoints (POST and DELETE) to update the updated_at field when adding or removing sessions for a registrant.
• Ensured consistency in timestamp updates for better data tracking and integration.

Waitlists

• Improved waitlist endpoints (POST and DELETE) to trigger updates to the updated_at field when managing waitlist entries for a session.
• Added support for timestamp updates to facilitate filtering and synchronization for external applications.