🐛[BUG] Legend is undefined when working with Venn Chart

[thoaihuynh2509]

🐛 bug 描述 [详细地描述 bug，让大家都能理解]

I copied venn chart from example but legend undefined is existed?

📷 复现步骤 [清晰描述复现步骤，让别人也能看到问题]

🏞 期望结果 [描述你原本期望看到的结果]

Please remove legend is undefined.

💻 复现代码 [提供可复现的代码，仓库，或线上示例]

https://ant-design-charts.antgroup.com/en/examples/statistics/venn/#basic

© 版本信息

• ant-design-charts 版本: [e.g. 2.0.0]
• 浏览器环境
• 开发环境 [e.g. mac OS]

🚑 其他信息 [如截图等其他信息可以贴在这里]