[Bug] yAxis with max < 1e-19 triggers assertion error in v6.1.0

### Version

6.1.0

### Link to Minimal Reproduction

https://codesandbox.io/p/sandbox/pensive-dewdney-vspmvt

### Steps to Reproduce

1. Open CodeSandbox link
2. See displayed error because chart cannot render
3. Change max value in value yAxis from 2.324097633474072e-20 to 2.324097633474072e-19
4. Chart renders now

### Current Behavior

When `yAxis.max` is smaller than approximately `1e-19` (for example `2.324097633474072e-20`), calling `chart.setOption()` throws an assertion error and the chart fails to render.

The error originates from `IntervalScale.setConfig` and propagates through the axis tick calculation (`axisNiceTicks` / `axisHelper`).

The same configuration works correctly in ECharts 6.0.0, so this appears to be a regression introduced in 6.1.0.

### Expected Behavior

The chart should render successfully regardless of how small the numeric `yAxis.max` value is, as long as it is a valid finite number.

Very small values (such as `2.324097633474072e-20`) should be handled correctly during axis tick calculation without triggering an assertion error or causing `chart.setOption()` to fail.

### Environment

```markdown
- OS: Ubuntu 22.04.4 LTS
- Browser: Firefox 151.0
- Framework: Angular@21
```

### Any additional comments?

I was initially unable to reproduce the issue in the official ECharts example editor because it currently appears to use ECharts 6.0.0 (or lower?), where the issue does not occur.

The assertion error is reproducible only with ECharts 6.1.0. Therefore, a standalone reproduction (e.g. CodeSandbox using 6.1.0) is required to observe the problem.