fix fcs shipment service

lib/domain/entities/fcs_shipment.dart

@@ -1,7 +1,5 @@
 import 'package:cloud_firestore/cloud_firestore.dart';
 
-import '../constants.dart';
-
 class FcsShipment {
   String? id;
   String? shipmentNumber;
@@ -66,10 +64,6 @@ class FcsShipment {
     };
   }
 
-  bool isConfirmed() {
-    return status == fcs_shipment_confirmed_status;
-  }
-
   bool isChangedForEdit(FcsShipment fcsShipment) {
     return fcsShipment.shipmentNumber != this.shipmentNumber ||
         fcsShipment.cutoffDate != this.cutoffDate ||