added alarm type

lib/model/callback_models/create_alarm_request.dart

@@ -1,3 +1,7 @@
+import '../alarm.dart' show AlarmType;
+
 class CreateAlarmRequest {
-  const CreateAlarmRequest();
+  const CreateAlarmRequest({required this.alarmType});
+
+  final AlarmType alarmType;
 }

lib/model/callback_models/create_location_alarm_request.dart

@@ -1,3 +1,4 @@
+import '../alarm.dart' show AlarmType;
 import '../location.dart';
 import 'create_alarm_request.dart';
 
@@ -6,5 +7,6 @@ class CreateLocationAlarmRequest extends CreateAlarmRequest {
 
   final int? radiusMeters;
 
-  const CreateLocationAlarmRequest({this.location, this.radiusMeters});
+  const CreateLocationAlarmRequest({this.location, this.radiusMeters})
+    : super(alarmType: AlarmType.location);
 }

lib/model/callback_models/create_time_alarm_request.dart

@@ -3,5 +3,5 @@ import 'create_alarm_request.dart';
 class CreateTimeAlarmRequest extends CreateAlarmRequest {
   final DateTime? triggerAt;
 
-  CreateTimeAlarmRequest({this.triggerAt});
+  CreateTimeAlarmRequest({this.triggerAt, required super.alarmType});
 }