[Bug] setting duration as a function does not work correctly.

### Version

2.0.12

### Link to Minimal Reproduction

https://www.visactor.com/vchart/playground?specId=0450757730&timestamp=1766663564770&version=2.0.11&theme=light

### Steps to Reproduce

link中demo可以复现

### Current Behavior

函数被调用，但是无法正常生效

### Expected Behavior

能正确使用函数返回值

### Environment

```markdown
- OS:
- Browser:
- Framework:
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### Any additional comments?

_No response_