Implement invoice revert functionality and enhance progress tracking

- Added a new route for reverting invoices in the A76 module.
- Updated the pre_validators to provide clearer error messages when processing invoices.
- Enhanced the PDF progress dialog to support step-by-step progress tracking for both invoice processing and reverting.
- Introduced a confirmation dialog for reverting invoices in the dashboard.
- Updated frontend components to handle the new revert functionality and display appropriate progress messages.

backend/api/v1/modules/a24/discharges/models.py

@@ -26,7 +26,6 @@ import datetime
 from decimal import Decimal
 from enum import Enum
 from typing import TYPE_CHECKING, List, Optional
-from ..discharges.models import DischargeDetail
 
 from sqlalchemy import (
     BigInteger,