Allow 3.5-turbo instruct models in the OpenAI LLM class (#10750)

@baskaryan @hwchase17

libs/langchain/langchain/llms/openai.py

@@ -196,7 +196,9 @@ class BaseOpenAI(BaseLLM):
     def __new__(cls, **data: Any) -> Union[OpenAIChat, BaseOpenAI]:  # type: ignore
         """Initialize the OpenAI object."""
         model_name = data.get("model_name", "")
-        if model_name.startswith("gpt-3.5-turbo") or model_name.startswith("gpt-4"):
+        if (
+            model_name.startswith("gpt-3.5-turbo") or model_name.startswith("gpt-4")
+        ) and not model_name.endswith("-instruct"):
             warnings.warn(
                 "You are trying to use a chat model. This way of initializing it is "
                 "no longer supported. Instead, please use: "