feat: billing cancel

external/billing/schemas.py

@@ -45,6 +45,14 @@ class CreateBillRequestSchema(BaseSchema):
         return None
 
 
+class DeleteBillRequestSchema(BaseSchema):
+    listener_transaction_id: int
+
+
+class DeleteBillResponseSchema(BaseSchema):
+    ok: bool
+
+
 class NotifyReceivedBillRequestSchema(BaseSchema):
     listener_transaction_id: int
     channel: NotificationChannel