check null safety

lib/domain/entities/setting.dart

@@ -9,21 +9,20 @@ List<Day> dayLists = [
 ];
 
 class Setting {
-  final int supportBuildNum;
-
+  final int? supportBuildNum;
   // contact page
-  String usaAddress;
-  String mmAddress;
-  String usaContactNumber;
-  String mmContactNumber;
-  String emailAddress;
-  String facebookLink;
-  bool inviteRequired;
-  String appUrl;
-  final String termsEng;
-  final String termsMm;
-  String about;
-  String courierWebsite;
+  String? usaAddress;
+  String? mmAddress;
+  String? usaContactNumber;
+  String? mmContactNumber;
+  String? emailAddress;
+  String? facebookLink;
+  bool? inviteRequired;
+  String? appUrl;
+  final String? termsEng;
+  final String? termsMm;
+  String? about;
+  String? courierWebsite;
 
   List<String> shipmentTypes;
 
@@ -40,7 +39,7 @@ class Setting {
       this.termsEng,
       this.termsMm,
       this.about,
-      this.shipmentTypes,
+      this.shipmentTypes = const [],
       this.courierWebsite});
 
   factory Setting.fromMap(Map<String, dynamic> map) {
@@ -76,9 +75,9 @@ class Setting {
 }
 
 class Day {
-  int id;
-  String name;
-  bool isChecked = false;
+  int? id;
+  String? name;
+  bool? isChecked = false;
   Day({this.id, this.name, this.isChecked});
 
   @override