[Bug] Text Outline not changeable

### Version

5.3.0

### Link to Minimal Reproduction

_No response_

### Steps to Reproduce

On the [theme builder](https://echarts.apache.org/en/theme-builder.html) select the dark theme, you'll notice on the pie chart that the legends (the ones circled in red on my screenshot), are outlined in white which renders poorly on dark theme

### Current Behavior

The legend of the pie chart is outlined in white

### Expected Behavior

The legend of the pie chart should be either outlined with a color that's configurable or not be outlined at all.

### Environment

```markdown
- OS: Archlinux 5.16.14-arch1-1
- Browser: Firefox Developer Edition 99.0b3
- Framework: React@17
```

### Any additional comments?

_No response_