parallel.axisExpandable example in documentation doesn't work

### Version
5.0.2

### Reproduction link
[https://echarts.apache.org/en/option.html#parallel.axisExpandable](https://echarts.apache.org/en/option.html#parallel.axisExpandable)

### Steps to reproduce
Go to https://echarts.apache.org/en/option.html#parallel.axisExpandable

### What is expected?
parallel.axisExpandable example should show up

### What is actually happening?
Nothing is shown.

Open the linked parallel.axisExpandable documentation page and reproduce the empty example in Apache ECharts documentation version 5.0.2. Trace the example configuration and its rendering entry point, then verify that the example displays as expected on the linked page.

Written by the indexing model from the issue text.