[Bug] CustomView emphasis.hoverLayer not control by hoverLayerThreshold

### Version

5.5.1

### Link to Minimal Reproduction

https://echarts.apache.org/examples/zh/editor.html?c=flame-graph

### Steps to Reproduce

Based on the official flame graph demo, using a large amount of data (more than 5000).

### Current Behavior

When hovering the mouse over a block, the text in the flame graph is blocked, and hoverLayerThreshold cannot be used to control whether a separate hover layer is enabled.

### Expected Behavior

When hovering the mouse over a block, the text in the flame graph displays correctly, or hoverLayerThreshold can be used to control whether a separate hover layer is enabled.

### Environment

```markdown
- OS: Macos
- Browser: Chrome
- Framework:
```

### Any additional comments?

after debugger, this code set `emphasis.hover = true` when use a large amount of data .