fix: The image of the image understanding node selects the image generated by the preceding node.

--bug=1050695 --user=刘瑞斌 【应用编排】图片理解节点的图片选择前置节点生成的图片，执行详情中加载失败 https://www.tapd.cn/57709429/s/1635547

apps/application/flow/step_node/image_generate_step_node/impl/base_image_generate_node.py

@@ -46,7 +46,7 @@ class BaseImageGenerateNode(IImageGenerateNode):
             }
             file_url = FileSerializer(data={'file': file, 'meta': meta}).upload()
             file_urls.append(file_url)
-        self.context['image_list'] = file_urls
+        self.context['image_list'] = [{'file_id': path.split('/')[-1], 'url': path} for path in file_urls]
         answer = '\n'.join([f"![Image]({path})" for path in file_urls])
         return NodeResult({'answer': answer, 'chat_model': tti_model, 'message_list': message_list,
                            'image': [{'file_id': path.split('/')[-1], 'file_url': path} for path in file_urls],