TF-1204 Add firebase object and capability

fcm/lib/model/firebase_expired_time.dart

@@ -0,0 +1,13 @@
+
+import 'package:equatable/equatable.dart';
+import 'package:jmap_dart_client/jmap/core/utc_date.dart';
+
+class FirebaseExpiredTime with EquatableMixin {
+
+  final UTCDate value;
+
+  FirebaseExpiredTime(this.value);
+
+  @override
+  List<Object?> get props => [value];
+}