Images has wrong css width percent when exported to html

### Description

using 0.14.0-rc.1

For example:

```typst
#image("xxx.jpg", width: 25%)
#image("xxx.jpg", width: 2500%)
```

produces:

```html
<img src="..." style="width: 0.25%">
<img src="..." style="width: 25%">
```



### Reproduction URL

_No response_

### Operating system

Windows

### Typst version

- [x] I am using the latest version of Typst