Allow mentees to revoke their applications

[Madhawa97]

Is your feature request related to a problem? Please describe. Mentees cannot revoke an application once submitted.

Describe the solution you'd like Implement functionality for mentees to revoke their submitted applications.

Describe alternatives you've considered

• [ ] Implement frontend UI for the revoke action
• [ ] Add confirmation dialog before revoking
• [ ] Update application status in the database upon revocation
• [ ] Ensure revoked applications are filtered out from mentor views

Additional context Add any other context or screenshots about the feature request here