🐛 [BUG]设置timeCat，brush-x无法使用

设置timeCat，brush-x无法使用
### 📷 Step to reproduce
```
import { Line } from '@antv/g2plot';

fetch('https://gw.alipayobjects.com/os/bmw-prod/1d565782-dde4-4bb6-8946-ea6a38ccf184.json')
.then((res) => res.json())
.then((data) => {
const line = new Line('container', {
data,
padding: 'auto',
xField: 'Date',
yField: 'scales',
xAxis: {
type: 'timeCat',
},
interactions: [
{
type: 'brush-x'
}
]
});

line.render();
});

```

Start by running the provided Line chart reproduction with xAxis.type set to timeCat and the brush-x interaction enabled. Trace the brush-x interaction and timeCat axis behavior to identify why brushing cannot be used; done means the example supports brush selection without breaking the time-based x-axis.

Written by the indexing model from the issue text.