fix: Use bind_tools API to bind all tools with LLM.

This is required to use tool calling feature.

llm_demo/orchestrator/langchain_tools/langchain_tools_orchestrator.py

@@ -70,6 +70,7 @@ def initialize_agent(
         model: str,
     ) -> "UserAgent":
         llm = ChatVertexAI(max_output_tokens=512, model_name=model, temperature=0.0)
+        llm.bind_tools(tools)
         memory = ConversationBufferMemory(
             chat_memory=ChatMessageHistory(messages=history),
             memory_key="chat_history",