[Feature Request] x.ai新api功能，Live search支持

### 🥰 需求描述

https://docs.x.ai/docs/guides/live-search
x.ai的api增加了live search的支持，通过参数可以选择

### 🧐 解决方案

import os
import requests

url = "https://api.x.ai/v1/chat/completions"
headers = {
"Content-Type": "application/json",
"Authorization": f"Bearer {os.getenv('XAI_API_KEY')}"
}
payload = {
"messages": [
{
"role": "user",
"content": "Provide me a digest of world news in the last 24 hours."
}
],
"search_parameters": {
"mode": "auto"
},
"model": "grok-3-latest"
}

response = requests.post(url, headers=headers, json=payload)
print(response.json())

简单的例子，json形式的一个新参数和三个选项可以提供开关，文档如上
还有一个返回的参数，应该只需要增加这两个就可以

### 📝 补充信息

_No response_