community[docs]: modify parameter for the LoRA adapter on the vllm page (#27930)

**Description:** 
This PR modifies the documentation regarding the configuration of the
VLLM with the LoRA adapter. The updates aim to provide clear
instructions for users on how to set up the LoRA adapter when using the
VLLM.

- before
```python
VLLM(..., enable_lora=True)
```
- after
```python
VLLM(..., 
    vllm_kwargs={
        "enable_lora": True
    }
)
```
This change clarifies that users should use the vllm_kwargs to enable
the LoRA adapter.

Co-authored-by: Um Changyong <changyong.um@sfa.co.kr>

docs/docs/integrations/llms/vllm.ipynb

@@ -266,8 +266,18 @@
     "from langchain_community.llms import VLLM\n",
     "from vllm.lora.request import LoRARequest\n",
     "\n",
-    "llm = VLLM(model=\"meta-llama/Llama-2-7b-hf\", enable_lora=True)\n",
-    "\n",
+    "llm = VLLM(\n",
+    "    model=\"meta-llama/Llama-3.2-3B-Instruct\",\n",
+    "    max_new_tokens=300,\n",
+    "    top_k=1,\n",
+    "    top_p=0.90,\n",
+    "    temperature=0.1,\n",
+    "    vllm_kwargs={\n",
+    "        \"gpu_memory_utilization\": 0.5,\n",
+    "        \"enable_lora\": True,\n",
+    "        \"max_model_len\": 350,\n",
+    "    },\n",
+    ")\n",
     "LoRA_ADAPTER_PATH = \"path/to/adapter\"\n",
     "lora_adapter = LoRARequest(\"lora_adapter\", 1, LoRA_ADAPTER_PATH)\n",
     "\n",