TF-831: implement Add a new recipient in forwarding

lib/features/manage_account/domain/state/add_recipient_in_forwarding_state.dart

@@ -0,0 +1,21 @@
+import 'package:core/presentation/state/failure.dart';
+import 'package:core/presentation/state/success.dart';
+import 'package:forward/forward/tmail_forward.dart';
+
+class AddRecipientsInForwardingSuccess extends UIState {
+  final TMailForward forward;
+
+  AddRecipientsInForwardingSuccess(this.forward);
+
+  @override
+  List<Object?> get props => [forward];
+}
+
+class AddRecipientsInForwardingFailure extends FeatureFailure {
+  final dynamic exception;
+
+  AddRecipientsInForwardingFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}