[Bug] [Line Chart] symbol: "none" causes the label not to show

### Version

5.6.0

### Link to Minimal Reproduction

[demo](https://echarts.apache.org/examples/zh/editor.html?c=line-simple&code=PYBwLglsB2AEC8sDeAoWsAeBBDEDOAXMmurGAJ4gCmRA5AMYCGYVA5sAE7m0A0J6AE2aMiAbVoBZGL1i0AKgFcqM2gHUqAlXIAWClQDEOEFQGVmphdFoBdEgF8-6cjnxFUpMpRqyAbowA2SrT2jrB4VEZUhLCi_MQegsJiAIwArAAMPLAATADMmTnZACxZ2ckAHFnJualVRQDspQBs6dahHhTUdP4Q0MrtpP6MAEZU_m5xHnjawADuRGAcSgMeAGYwYOoQrNpgdNCcALYBvJOk69BgJhT-3rQHHMf-pwmkLBhgAEKcAhEAwsB_Jw6BxWMNGAAKbKpWo5GGleGwZIASherzIVA-3w4vw4qggAjA2iImTO6BAwDwEEgMDowAUYCpv2CrwcZzw5EOw0B-xg_TidhItjsAG4gA)

### Steps to Reproduce

After adding `symbol: "none"`, the series label disappeared unexpectedly.

### Current Behavior

line series label lost

### Expected Behavior

show labels normally

### Environment

```markdown
- OS:
- Browser:
- Framework:
```

### Any additional comments?

_No response_