adding missing dependency

LG_agent.py

@@ -1,7 +1,7 @@
 from langchain_huggingface import HuggingFaceEndpoint, ChatHuggingFace
 from typing import Annotated, TypedDict
 from langgraph.graph.message import add_messages
-from langchain_core.messages import HumanMessage, AIMessage
+from langchain_core.messages import HumanMessage, AIMessage, AnyMessage
 from tools import search_duckduckgo
 from langgraph.prebuilt import tools_condition