[Bug Report] form inline模式下size 为small或者mini时，DatePicker组件与其他控件没对齐

### Element UI version
2.15.9

### OS/Browsers version
5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

### Vue version
2.7.8

### Reproduction Link
https://codepen.io/mrz9/pen/qBoKayd

### Steps to reproduce
将form控件的size设置为small或者mini后，DatePicker组件上边框与其他控件上边框没对齐

### What is Expected?
DatePicker组件应该与其他控件对其

### What is actually happening?
DatePicker组件比其他控件高大概1px