🤔 [QUESTION] 分组柱状图，如何配置默认第一组数据 active-region:show

### 🐛 Question description [Please make everyone to understand it]

### 💻 Link to minimal reproduction

[官网分组柱状图例子](https://antv-g2plot.gitee.io/zh/examples/column/grouped#basic)

### 🏞 Expected result，默认第一组数据是 active-region:show 状态

### 🚑 Any additional [like screenshots]
还有如图配置点击element，激活active-region的方式对吗？

* **G2Plot Version**: last
* **Platform**: windows

Start with the linked grouped column example and review its active-region configuration and element interaction setup. Confirm how the first data group can be active by default, and verify the resulting chart behavior against the expected screenshots.

Written by the indexing model from the issue text.