[Bug] ECharts splitLine not showing on interval function

### Version

5.4.3

### Link to Minimal Reproduction

https://codepen.io/calabasssita/pen/wvNaJrd

### Steps to Reproduce

You can reproduce it also [on the examples editor:](https://echarts.apache.org/examples/en/editor.html?c=line-simple&theme=dark&code=PYBwLglsB2AEC8sDeAoWsAeBBDEDOAXMmurGAJ4gCmRA5AMYCGYVA5sAE7m0A0J6IYHgiQYdMKF79YAE2aMiAbVq9YtAEabVKnmu2MD22gF0-pWHhAAbEQBkI0GsXPo8AC2AB3ImA4BXKjMXBxYOADdGKyIAMz9oelFoAAoHGSoMXQirAIBKZxd0DiowPw44LIDYAEJEFQBuaXQAX2kW5qC5MEYALWBgAFslaVQCimo6PBs0jlpWoPQRlzGnWgdhNNnzNthTEnIcfCJF9GW6CqpN2CagvCoOCCpCWEVhxtl5JQBGAFYABl0AEwAZn-sABAIALLpPhCAOyAgBsoL-u1GlBWNkcl2aJGMKCadSAA)
There are splitLines under each data label when it's not an empty string:
```
option = {
xAxis: {
type: 'category',
position: 'top',
data: ['', 'bbb', '', '', 'aaa', ''],
splitLine: {
show: true,
interval: function(index, value) {
return value != '';
}
}
},
dataZoom: [
{
type: 'slider'
}
],
yAxis: {
type: 'value'
},
series: [
{
data: [150, 230, 224, 147, 260, 50],
type: 'line'
}
]
};
```

Change data do this, for example, the splitLine goes to the left side of the chart, and not under the data label:

```
data: ['', '', '', '', 'aaa', ''],
```

It also happens if you have data like this, and you zoom leaving only one label on the zoomed data

```
data: ['', 'bbb', '', '', 'aaa', ''],
```

### Current Behavior

The splitLines does not show under the label when there's only one not empty value in data, it also happens while having more than one not empty values if you zoom the chart so only one one not empty value is shown.

### Expected Behavior

To have a splitLine under the data label when it satisfies the function.

### Environment

```markdown
- OS:macOs Ventura 13.4
- Browser: Firefox version 118.0.2 (64-bit)
- Framework:
```

### Any additional comments?

If there's a workaround, to only show the splitLines when a value is different from X it would also help, Thanks.