[Bug] SVG shadow width with lineStyle

### Version

5.5.1

### Link to Minimal Reproduction

https://echarts.apache.org/examples/en/editor.html?c=line-smooth&version=5.5.1&renderer=svg&code=PYBwLglsB2AEC8sDeAoWsAeBBDEDOAXMmuqemAJ4gCmRA5AMYCGY1A5sAE4V0A0JAX37oKOfEVRlKNegDcmAGwCu1PoOGw81ThGqFYAbRLpJZWABMWTIgYCMvWPccOnrgHQAGL7YC6GqVS0sHQKENCq_qR4ABbAAO4AyhQAtgBGwApEAGaKWpHooeEJlApBpmZmcRDmYNFEACz5FbDMIPScwErQ5mrNZjFM5vEAwhlc9ADEWV69fVHRg_EAQsqcRACsTRUDQ3EA8llZWmAAGkS2Hlv9C7sHR9RgAJrnl8ZmQm8CJD4oAgDcQA

### Steps to Reproduce

1. Create a line series with data that's almost the same
2. Set lineStyle.width to be 4
3. Use SVG renderer to see the width of the line is not correct

### Current Behavior

Line width is thinner than 4px when renderer is SVG but 4px when with Canvas.

### Expected Behavior

Line width should be 4px, which is the same as canvas.

### Environment

```markdown
- OS:
- Browser:
- Framework:
```

### Any additional comments?

_No response_

Start with the linked minimal reproduction using ECharts 5.5.1, the SVG renderer, and a line series whose lineStyle.width is 4. Compare its rendered width with the Canvas renderer for nearly identical data. Done means the SVG line is visibly 4px and matches Canvas.

Written by the indexing model from the issue text.