refactor: enhance refund ticket logic and role-based access control

- Updated the RefundTicket schema to allow both customers and center mentors to request refunds, improving flexibility in refund processing.
- Refined bank detail checks to differentiate between customers and center mentors, ensuring appropriate handling of bank information.
- Implemented special handling for center mentors to always allow full refunds, enhancing user experience.
- Improved error messages and validation checks throughout the refund process for better clarity and user guidance.

src/Quiz/quiz.schema.ts

@@ -212,7 +212,6 @@ export class QuizSchema extends PothosSchema {
               'centerMentorId',
               'createdAt',
               'updatedAt',
-              'service',
             ]),
             required: true,
           }),