Fixes bug in fontsource.ts when style is normal

[holgerkoser]

Problem

Currently, the plugin configuration

Unfonts({
  fontsource: {
    families: [
      {
        name: 'Roboto',
        weights: [400],
        styles: ['normal', 'italic'],
        subset: 'latin',
      },
    ],
  },
}),

generates an error:

[vite:css] [postcss] ENOENT: no such file or directory, open '@fontsource/roboto/latin-normal.css'
file: unfonts.css:undefined:undefined
error during build:
Error: [postcss] ENOENT: no such file or directory, open '@fontsource/roboto/latin-normal.css'

Expected Solution

The configuration should lead to the successful loading of the following files:

@fontsource/roboto/latin-400.css
@fontsource/roboto/latin-400-italic.css

If the style is set to normal, the style should not be included in the file name; instead, the weight should be retained.