[Mypy] Better fixes for the mypy issues in vllm/config (#37902)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/entrypoints/offline_mode/test_offline_mode.py

@@ -2,7 +2,6 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Tests for HF_HUB_OFFLINE mode"""
 
-import dataclasses
 import importlib
 import sys
 
@@ -12,7 +11,6 @@ import urllib3
 
 from vllm import LLM
 from vllm.distributed import cleanup_dist_env_and_memory
-from vllm.engine.arg_utils import EngineArgs
 
 MODEL_CONFIGS = [
     {
@@ -160,8 +158,7 @@ def test_model_from_huggingface_offline(monkeypatch: pytest.MonkeyPatch):
             # Need to re-import huggingface_hub
             # and friends to set up offline mode
             _re_import_modules()
-            engine_args = EngineArgs(model="facebook/opt-125m")
-            LLM(**dataclasses.asdict(engine_args))
+            LLM(model="facebook/opt-125m")
         finally:
             # Reset the environment after the test
             # NB: Assuming tests are run in online mode