[Bug] Unexpected behavior when using stacked lines in chart with x-axis of type 'value'

### Version

5.4.3

### Link to Minimal Reproduction

https://echarts.apache.org/examples/en/editor.html?c=line-simple&code=MYewdgzgLgBAJgQygmBeGYCmB3GAxAGxCQGYAmAQQCcqEBPACgG0AoGGARgBoYSeyAdAA4eABgF8YZfgICsM6THHzeMgOwyAbCvEcWAXQCUAbhahIsOAEsAtpkhXwENDCYByAB5uebgG7eYNwIAtwBXN31TFhAAByhHMBcAbzYYKBAQAniYgC4YFPZ2KCorAHNSzCo8tysoTBtvVPYEDysIAAUQKzA6qvymwqg6GMxq4CoQCAhGwsKEMFskBLyAMwQCCEwBgF9U7a5UjwpWiDyCweHRwN910MwZwohgdaviu72D9jpjtrOBoZG1RuBDubg-qU2JUwp1cA3OswBVyC3Xun1mMHsoDgVySMA81S8PDo1WCMH2A3YiGQaNm1jsDicNMKBBRAGUhgQcRTCrEEMBasTONzyeiYNA-QBrMbgFZWbFgYCYAC0ACN5nAHrMIHQbCrMtUwOB7jsmfCLoDAiysJrCpiQNizniCQFBWE3GSmZSkAhPfBbPYIAkIL6rZh2XROX9Rexefyhnk9KKRejxcApYFzLL5YrVerGtyEFRMAhw5H-tGYKAiH03ABiYANsFJk1w7mIkkom3sO0O_JOwKEmCu_we7lUn1j_0MyA7VL6FjbYxAA

### Steps to Reproduce

- Create a line chart with stacked lines
- Set both axes to `type: 'value'`
- Fill the area between two lines of the stack

### Current Behavior

The stacked line gets stacked on the values of the x-axis.

### Expected Behavior

The stacked line gets stacked on the values of the y-axis, the same behavior as if the x-axis was of type 'category'.

### Environment

```markdown
- OS: Windows 10 Enterprise
- Browser: Chrome 120.0.6099.71
- Framework: None
```

### Any additional comments?

Or are there other options for filling arbitrary areas between two lines, or between one line and one particular axis?