[Bug] Fix wrong modescope env set order (#1611)

### What this PR does / why we need it?
The `os.environ["VLLM_USE_MODELSCOPE"] = "True"` should be placed before
module imports

if not 
```
The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/xleoken/projects/vllm-ascend/examples/offline_embed.py", line 48, in <module>
    model = LLM(model="Qwen/Qwen3-Embedding-0.6B", task="embed")
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/vllm/entrypoints/llm.py", line 243, in __init__
    self.llm_engine = LLMEngine.from_engine_args(
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/vllm/engine/llm_engine.py", line 494, in from_engine_args
    vllm_config = engine_args.create_engine_config(usage_context)
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/vllm/engine/arg_utils.py", line 1018, in create_engine_config
    model_config = self.create_model_config()
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/vllm/engine/arg_utils.py", line 910, in create_model_config
    return ModelConfig(
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/pydantic/_internal/_dataclasses.py", line 120, in __init__
    s.__pydantic_validator__.validate_python(ArgsKwargs(args, kwargs), self_instance=s)
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/vllm/config.py", line 528, in __post_init__
    hf_config = get_config(self.hf_config_path or self.model,
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/vllm/transformers_utils/config.py", line 321, in get_config
    config_dict, _ = PretrainedConfig.get_config_dict(
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/transformers/configuration_utils.py", line 590, in get_config_dict
    config_dict, kwargs = cls._get_config_dict(pretrained_model_name_or_path, **kwargs)
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/transformers/configuration_utils.py", line 649, in _get_config_dict
    resolved_config_file = cached_file(
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/transformers/utils/hub.py", line 266, in cached_file
    file = cached_files(path_or_repo_id=path_or_repo_id, filenames=[filename], **kwargs)
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/transformers/utils/hub.py", line 491, in cached_files
    raise OSError(
OSError: We couldn't connect to 'https://huggingface.co' to load the files, and couldn't find them in the cached files.
Checkout your internet connection or see how to run the library in offline mode at 'https://huggingface.co/docs/transformers/installation#offline-mode'.
[ERROR] 2025-07-03-15:27:10 (PID:333665, Device:-1, RankID:-1) ERR99999 UNKNOWN applicaiton exception
```

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?

Local.

Signed-off-by: xleoken <xleoken@163.com>

Author: xleoken

examples/offline_embed.py

@@ -18,13 +18,11 @@
 #
 
 import os
+os.environ["VLLM_USE_MODELSCOPE"] = "True"
 
 import torch
 from vllm import LLM
 
-os.environ["VLLM_USE_MODELSCOPE"] = "True"
-
-
 def get_detailed_instruct(task_description: str, query: str) -> str:
     return f'Instruct: {task_description}\nQuery:{query}'