🐛 [BUG] 分组柱状图仅有一组数据时，与dodgePadding属性冲突，导致不渲染柱图

### 🐛 Bug description
分组柱状图仅有一组数据时，与dodgePadding属性冲突，导致不渲染柱图

### 📷 Step to reproduce
```js
import { Column } from '@antv/g2plot';

const data = [
{
name: 'London',
月份: 'Jan.',
月均降雨量: 18.9,
},
{
name: 'Berlin',
月份: 'Jan.',
月均降雨量: 12.4,
},
];

const plot = new Column('container', {
data,
isGroup: true,
dodgePadding: 40,
xField: '月份',
yField: '月均降雨量',
seriesField: 'name',
interactions: [{ type: 'element-selected' }]
});

plot.render();
```

### 🏞 Expected result

### 🚑 Any additional [like screenshots]

* **G2Plot Version**:
* **Platform**:

Start from the Column entry point and reproduce the configuration shown with one data group, isGroup enabled, and dodgePadding set to 40. Compare the rendered result with the expected screenshot, then verify that the grouped column renders correctly without removing dodgePadding. Confirm the fix with the provided reproduction case.

Written by the indexing model from the issue text.