[Bug Report] el-date-picker component drop-down box content duplication problem

### Element UI version
2.15.14

### OS/Browsers version
Chrome 121.0.6167.184

### Vue version
2.7.16

### Reproduction Link
https://codepen.io/pen

### Steps to reproduce

Set the format of the component to yyyy year MM month dd day HH:mm, and the repeated 'day' will appear in front of the drop-down box when selecting a time

### What is Expected?
I want the two input fields in the drop down to correctly separate the year, month, day and hour and split them together

### What is actually happening?
The content in the component input box is not properly split in the two input fields of the drop-down box, and duplicate content appears