🤔 [QUESTION] Unable to customize the label of X axis. (Radar Chart)

### 🐛 Question description
I want to add a border for the label of X axis in the Radar Chart

### 💻 Link to minimal reproduction

```{JavaScript}
xAxis: {
label: {
style: {
fontFamily: "'Inter', sans-serif",
fontWeight: 500,
fontSize: 20,
fill: "#0C0D21",
border: "1px solid #F1F1F7",
background: "#6a6a6a",
className: styles.xAxisLabel,
},
formatter: (text, item, index) => {
const userAScore = data.find(
(d) => d.item === text && d.user === "User A"
).actualScore;
const userBScore = data.find(
(d) => d.item === text && d.user === "User B"
).actualScore;
return `${text} (A: ${userAScore}, B: ${userBScore})`;
},
useHtml: true,
htmlTemplate: (text) => `

`,
},
```

```{css}
.xAxisLabel {
border: 3px solid #000 !important;
padding: 2px;
background-color: #fff;
}
```
### 🏞 Expected result
I tried add border using HTML or using className to define. but all failed. I checked the doc, but I did not find an example to support this.
if this is achievable?

* **G2Plot Version**: "@antv/g2plot": "^2.4.31",
* **Platform**: Win11

Start by reviewing the Radar Chart xAxis label configuration shown in the issue, including style, useHtml, htmlTemplate, and className. Determine whether bordered labels are supported in G2Plot 2.4.31; done means documenting the supported approach or identifying the required chart behavior and validating it with a minimal reproduction.

Written by the indexing model from the issue text.