fix(schemas/theme.json): use anyOf in determining mime or url

[soraxas]

The language stated in https://yazi-rs.github.io/docs/configuration/theme is unclear

noting that it must be used with either url or mime. It accepts the following values:

But in code, https://github.com/sxyazi/yazi/blob/0c8c973e6c766ff026665e487a33ad82f0c7e4f8/yazi-config/src/theme/filetype.rs#L37-L40

impl FiletypeRule {
	pub fn matches(&self, file: &File, mime: &str) -> bool {
		if !self.is.check(&file.cha) {
			return false;
		}

		self.mime.as_ref().is_some_and(|p| p.match_mime(mime))
			|| self.url.as_ref().is_some_and(|n| n.match_url(&file.url, file.is_dir()))
	}
}

you can see that the filter supports either OR; not XOR.

Using anyOf fixes the lint error like:

{"mime":"message/rfc822","url":"*.eml","bold":true,"fg":"#870087"} is 
valid under more than one of the schemas listed in the 'oneOf' keywordEven Better TOML

when both mime and url are used.