swift 接入数据集下载后还是会不断请求网络

[fly-dragon211]

Describe the feature
数据集最开始是下载好了，但是代码运行过程中好像会去请求数据集网络，有时网络会卡，造成训练中断。

[rank3]: OSError: Tunnel connection failed: 503 Service Unavailable[rank3]: The above exception was the direct cause of the following exception:[rank3]: urllib3.exceptions.ProxyError: ('Unable to connect to proxy', OSError('Tunnel connection failed: 503 Service Unavailable'))[rank3]: The above exception was the direct cause of the following exception:[rank3]: Traceback (most recent call last):[rank3]:   File "/data/miniconda3/envs/env-3.11.9/lib/python3.11/site-packages/requests/adapters.py", line 667, in send[rank3]:     resp = conn.urlopen([rank3]:            ^^^^^^^^^^^^^[rank3]:   File "/data/miniconda3/envs/env-3.11.9/lib/python3.11/site-packages/urllib3/connectionpool.py", line 843, in urlopen[rank3]:     retries = retries.increment([rank3]:               ^^^^^^^^^^^^^^^^^^[rank3]:   File "/data/miniconda3/envs/env-3.11.9/lib/python3.11/site-packages/urllib3/util/retry.py", line 519, in increment[rank3]:     raise MaxRetryError(_pool, url, reason) from reason  # type: ignore[arg-type][rank3]:     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^[rank3]: urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='xingchen-data.oss-cn-zhangjiakou.aliyuncs.com', port=443): Max retries exceeded with url: /coco/2014/val2014/COCO_val2014_000000165638.jpg (Caused by ProxyError('Unable to connect to proxy', OSError('Tunnel connection failed: 503 Service Unavailable')))

版本：ms-swift 2.2.0.dev0

#982 这里说可以设置 --custom_train_dataset_path ，但是这个参数已经被废止：https://github.com/modelscope/swift/blob/main/docs/source/LLM/%E5%91%BD%E4%BB%A4%E8%A1%8C%E5%8F%82%E6%95%B0.md

[Jintao-Huang]

--train_dataset 直接指定本地路径就好了