chore: dart fix

frontend/app_flowy/packages/appflowy_editor/lib/src/render/image/image_upload_widget.dart

@@ -3,7 +3,6 @@ import 'dart:collection';
 import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/editor_state.dart';
 import 'package:appflowy_editor/src/infra/flowy_svg.dart';
-import 'package:appflowy_editor/src/core/transform/transaction.dart';
 import 'package:appflowy_editor/src/render/selection_menu/selection_menu_service.dart';
 import 'package:flutter/material.dart';