[Bug]: edge设置endArrowOffset之后，label位置发生偏移

### Describe the bug / 问题描述

设置了箭头偏移endArrowOffset之后，label也发生了偏移：

没有设置是正常的：


### Reproduction link / 复现链接

https://stackblitz.com/edit/react-gxxq1caj?file=index.js

### Steps to Reproduce the Bug or Issue / 重现步骤

_No response_

### Version / 版本

Please select / 请选择

### OS / 操作系统

- [ ] macOS
- [ ] Windows
- [ ] Linux
- [ ] Others / 其他

### Browser / 浏览器

- [ ] Chrome
- [ ] Edge
- [ ] Firefox
- [ ] Safari (Limited support / 有限支持)
- [ ] IE (Nonsupport / 不支持)
- [ ] Others / 其他

Start with the linked StackBlitz React reproduction in index.js and compare edge label placement with and without endArrowOffset. Trace the G6 edge rendering or label-layout entry point responsible for the discrepancy, then verify that changing the arrow offset no longer moves the label unexpectedly.

Written by the indexing model from the issue text.