fix llm streamoptions issue (#1623)

Signed-off-by: letonghan <letong.han@intel.com>

Author: letonghan

comps/cores/proto/api_protocol.py

@@ -292,7 +292,7 @@ class ChatCompletionRequest(BaseModel):
     service_tier: Optional[str] = None
     stop: Union[str, List[str], None] = Field(default_factory=list)
     stream: Optional[bool] = False
-    stream_options: Optional[StreamOptions] = Field(default_factory=StreamOptions)
+    stream_options: Optional[StreamOptions] = Field(default=None)
     temperature: Optional[float] = 0.01  # vllm default 0.7
     top_p: Optional[float] = None  # openai default 1.0, but tgi needs `top_p` must be > 0.0 and < 1.0, set None
     tools: Optional[List[ChatCompletionToolsParam]] = None