[Bug] Firefox crashes when setting the itemStyle while using the SVG renderer

### Version

5.5.1

### Link to Minimal Reproduction

https://echarts.apache.org/examples/en/editor.html?c=bar-stack-normalization

### Steps to Reproduce

1. Use Firefox (latest version 132.0.1)
2. Go to the official bar chart example (https://echarts.apache.org/examples/en/editor.html?c=bar-stack-normalization)
3. Add the following definition to the series definition:
```javascript
itemStyle: {
shadowColor: '#000000',
shadowBlur: 0,
shadowOffsetX: 0,
shadowOffsetY: 1,
},
```
4. Switch to the SVG renderer
5. Firefox crashes

### Current Behavior

Firefox crashes when setting the itemStyle options

### Expected Behavior

Firefox should not crash

### Environment

```markdown
- OS: macOS 15.1 (happens in Windows too)
- Browser: Firefox 132.0.1
- Framework: Official ECharts website
```

### Any additional comments?

_No response_