🤔 高级图表中图例不显示问题，直接使用dot是可以展示的

### 🐛 Question description [Please make everyone to understand it]

### 💻 Link to minimal reproduction

Please provide a link by forking these links [L7Plot](https://codesandbox.io/s/l7plot-issue-template-ckpvq?file=/src/index.ts) or GitHub repo. What is a minimal reproduction, and why is it required?

### 🏞 Expected result

### 🚑 Any additional [like screenshots]

- **L7Plot Version**:
- **Platform**:

Start with src/index.ts in the linked L7Plot CodeSandbox minimal-reproduction template and compare the advanced chart configuration with the direct dot usage described in the issue title. Reproduce the missing legend, then record the affected L7Plot version and platform and verify that the legend appears in the advanced chart.

Written by the indexing model from the issue text.