fix(types/withDefaults): ensure default values of type any do not include undefined

[jh-leong]

In some edge cases, casting type with any is helpful when using withDefaults. However, currently, when the default values have any casting, it incorrectly includes the undefined type.

const _ = <T extends string>() => {
  const props = withDefaults(defineProps<{ foo?: T }>(), { foo: 'bar' as any })

  // before: T | NotUndefined<T> | undefined
  // after: NotUndefined<T>
  props.foo
}```

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	90.1 kB	34.5 kB	31.1 kB
vue.global.prod.js	147 kB	54 kB	48 kB

Usages

Name	Size	Gzip	Brotli
createApp	49.6 kB	19.5 kB	17.8 kB
createSSRApp	53.2 kB	20.9 kB	19.1 kB
defineCustomElement	51.9 kB	20.2 kB	18.5 kB
overall	63.1 kB	24.5 kB	22.3 kB