docs: update OctoAI LLM doc (#21528)

This PR updates OctoAI doc to remove warnings when running the example
code.

docs/docs/integrations/llms/octoai.ipynb

@@ -67,7 +67,7 @@
    "outputs": [],
    "source": [
     "llm = OctoAIEndpoint(\n",
-    "    model=\"llama-2-13b-chat-fp16\",\n",
+    "    model_name=\"llama-2-13b-chat-fp16\",\n",
     "    max_tokens=200,\n",
     "    presence_penalty=0,\n",
     "    temperature=0.1,\n",
@@ -83,9 +83,9 @@
    "source": [
     "question = \"Who was Leonardo da Vinci?\"\n",
     "\n",
-    "llm_chain = LLMChain(prompt=prompt, llm=llm)\n",
+    "chain = prompt | llm\n",
     "\n",
-    "print(llm_chain.run(question))"
+    "print(chain.invoke(question))"
    ]
   },
   {