fix: prevent HuggingFace access when SGLANG_USE_MODELSCOPE is enabled

[yankay]

Motivation

When SGLANG_USE_MODELSCOPE=true is set, the system was still making calls to HuggingFace endpoints during model configuration loading, which could lead to:

• Network access issues in environments where HuggingFace is blocked

Fix: #8275

Modifications

Referenced Vllm: vllm-project/vllm#5233
This PR fixes the issue by adding conditional import logic for AutoConfig and HfApi.

The problem can be reliably reproduced by setting HF_ENDPOINT: https://127.0.0.1, so a test case has been modified to ensure no HuggingFace access occurs when SGLANG_USE_MODELSCOPE is enabled.

Checklist

• Format your code according to the Code Formatting with Pre-Commit.
• Add unit tests as outlined in the Running Unit Tests.
• Update documentation / docstrings / example tutorials as needed, according to Writing Documentation.
• Provide throughput / latency benchmark results and accuracy evaluation results as needed, according to Benchmark and Profiling and Accuracy Results.
• For reviewers: If you haven't made any contributions to this PR and are only assisting with merging the main branch, please remove yourself as a co-author when merging the PR.
• Please feel free to join our Slack channel at https://slack.sglang.ai to discuss your PR.

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!

[yankay]

HI @merrymercy
Would you please help to review it :-)

[Vigilans]

Ping for a review.

[yankay]

HI @Fridge003 and @Kangyan-Zhou

Could you please help review it again?

[yankay]

close because of #12039 merged