Fix missing SQLAlchemy exists import in partner dashboard

app/modules/partner_dashboard/service.py

@@ -4,7 +4,7 @@ from datetime import date, timedelta
 from decimal import Decimal
 from typing import Any
 
-from sqlalchemy import func, or_, select
+from sqlalchemy import exists, func, or_, select
 from sqlalchemy.orm import Session, selectinload
 
 from app.modules.clients.association_models import ClientAssociation