removed langchain openai dependency

app.py

@@ -15,7 +15,7 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 
 from typing import TypedDict, List, Dict, Any, Optional, Annotated
 from langgraph.graph import StateGraph, START, END
-from langchain_openai import ChatOpenAI
+# from langchain_openai import ChatOpenAI
 # from langchain_huggingface.llms import HuggingFaceEndpoint
 from langchain_core.messages import AnyMessage, SystemMessage, HumanMessage
 from langgraph.graph.message import add_messages