[Bug] Axis type='category' is not auto retrieved from _dataset.source_

### Version

6.0.0

### Link to Minimal Reproduction

[Demo](https://echarts.apache.org/examples/en/editor.html?code=PTAEBMEsGcGMCcCmAHAhgO1gT1Jdv0AXReZJQ1QyAe32oDNRoTJFoA6cS1UDcCbs0Lto1AK7xYiAFAhQADwCC8mABosymKEJZkiALwByWJUQBzavCyHQigAoBJAFyhZYUKABEAYVMWrAhSgJvgARoi8YoTUoOTwrABuiPz08NQAtkwsbJzcoJaBqEIi4pKIntJcQfqgANrSHrUAjADsAJyqoIYAFpbM4RiGALqqDXVNAGwADJ09fYgD6MOjjQBMACzrswA2eMzJy2O1qy1NO3uIByNHGwDMs6JYi4drtzNdj8_Xa-sAHA_UJ6IQZDaRDADc0moyCotFANQA3mMqkVEIQXLUEa4PB4oOlEOhoDRCRjDAB3RCQMzdQiGWb0S7gZbYnGiCRSFwolkAX2-Ck00BcSJxoHQqHxLnJlOptLG3JWoA0KkFoGFOJ0eklJmI_msCo8YolXQZBzlCuY8TYQrGHg1iElcEoxHgdJthRFclgGXxRHyUW03S0u3QEWivFgVASpkKQjl0m54KAA)

### Steps to Reproduce

Comment out the marked line in the Demo to see the result.

### Current Behavior

API for [Axis.type](https://echarts.apache.org/en/option.html#xAxis.type) says that _"Category data can be auto retrieved from series.data or dataset.source"_.
While this is working for _series.data_, it is not happening for _dataset.source_ and the chart is seriously compromised.
This is important because only _dataset_ can have [transformations](https://echarts.apache.org/en/option.html#dataset.transform) and can be accessed by multiple series, _series.data_ cannot.

### Expected Behavior

_series.data_ and _dataset.source_ to be treated the same when auto-retrieving **category** data type

### Environment

```markdown

```

### Any additional comments?

When the two data columns are switched, dataset.source works ok, but series.data does not.