[Bugfix] Use lazy string reference for DeepseekV3Config in config registry (#28958)

Signed-off-by: Luke <yq0536@gmail.com>
Signed-off-by: Isotr0py <mozf@mail2.sysu.edu.cn>
Co-authored-by: Isotr0py <mozf@mail2.sysu.edu.cn>

vllm/transformers_utils/configs/__init__.py

@@ -5,8 +5,13 @@ Model configs may be defined in this directory for the following reasons:
 
 - There is no configuration file defined by HF Hub or Transformers library.
 - There is a need to override the existing config to support vLLM.
+- The HF model_type isn't recognized by the Transformers library but can
+  be mapped to an existing Transformers config, such as
+  deepseek-ai/DeepSeek-V3.2-Exp.
 """
 
+from transformers import DeepseekV3Config
+
 from vllm.transformers_utils.configs.afmoe import AfmoeConfig
 from vllm.transformers_utils.configs.chatglm import ChatGLMConfig
 from vllm.transformers_utils.configs.deepseek_vl2 import DeepseekVLV2Config
@@ -44,6 +49,7 @@ __all__ = [
     "AfmoeConfig",
     "ChatGLMConfig",
     "DeepseekVLV2Config",
+    "DeepseekV3Config",
     "DotsOCRConfig",
     "EAGLEConfig",
     "FlexOlmoConfig",