TF-832 Implement delete multiple recipient in forwarding

lib/features/manage_account/presentation/model/recipient_forward.dart

@@ -0,0 +1,35 @@
+
+import 'package:equatable/equatable.dart';
+import 'package:model/mailbox/select_mode.dart';
+
+class RecipientForward with EquatableMixin {
+  final String emailAddress;
+  final SelectMode selectMode;
+
+  RecipientForward(this.emailAddress, {this.selectMode = SelectMode.INACTIVE});
+
+  @override
+  List<Object?> get props => [emailAddress, selectMode];
+}
+
+extension RecipientForwardExtension on RecipientForward {
+
+  RecipientForward toggleSelection() {
+    return RecipientForward(
+      emailAddress,
+      selectMode: selectMode == SelectMode.ACTIVE
+          ? SelectMode.INACTIVE
+          : SelectMode.ACTIVE
+    );
+  }
+
+  RecipientForward cancelSelection() {
+    return RecipientForward(emailAddress, selectMode: SelectMode.INACTIVE);
+  }
+}
+
+extension ListRecipientForwardExtension on List<RecipientForward> {
+
+  Set<String> get listEmailAddress =>
+      map((recipient) => recipient.emailAddress).toSet();
+}