Stop using singleton instance on Dart bindings

Apply changes on Flutter plugin

libs/sdk-flutter/lib/generated/error.dart

@@ -0,0 +1,31 @@
+// This file is automatically generated, so please do not edit it.
+// Generated by `flutter_rust_bridge`@ 2.0.0-dev.36.
+
+// ignore_for_file: invalid_use_of_internal_member, unused_import, unnecessary_import
+
+import 'frb_generated.dart';
+import 'package:flutter_rust_bridge/flutter_rust_bridge_for_generated.dart';
+import 'package:freezed_annotation/freezed_annotation.dart' hide protected;
+part 'error.freezed.dart';
+
+@freezed
+sealed class ConnectError with _$ConnectError implements FrbException {
+  const ConnectError._();
+
+  /// This error is raised when a general error occurs not specific to other error variants
+  /// in this enum.
+  const factory ConnectError.generic({
+    required String err,
+  }) = ConnectError_Generic;
+
+  /// This error is raised when [crate::models::ConnectRequest::restore_only] is set to true
+  /// and no node exists for [crate::models::ConnectRequest::seed].
+  const factory ConnectError.restoreOnly({
+    required String err,
+  }) = ConnectError_RestoreOnly;
+
+  /// This error is raised when a connection to an external service fails.
+  const factory ConnectError.serviceConnectivity({
+    required String err,
+  }) = ConnectError_ServiceConnectivity;
+}