fix conversion command llama in llamaindex agent (#2671)

Author: eaidova

notebooks/llm-agent-react/llm-agent-rag-llamaindex.ipynb

@@ -221,7 +221,7 @@
     "    if repo_name == \"OpenVINO\":\n",
     "        hf_hub.snapshot_download(llm_model_id.value, local_dir=llm_model_path)\n",
     "    else:\n",
-    "        optimum_cli(llm_model_id.value, llm_model_path, additional_args=-{\"task\": \"text-generation-with-past\", \"weight-format\": \"int4\"})"
+    "        optimum_cli(llm_model_id.value, llm_model_path, additional_args={\"task\": \"text-generation-with-past\", \"weight-format\": \"int4\"})"
    ]
   },
   {