fix(css): remove alias exclude logic from rebaseUrl

[sapphi-red]

Description

This part of code was added by #2323.

vite/packages/vite/src/node/plugins/css.ts

Lines 2774 to 2783 in a33d0c7

	// match alias, no need to rewrite
	for (const { find } of alias) {
	const matches =
	typeof find === 'string'
	? unquotedUrl.startsWith(find)
	: find.test(unquotedUrl)
	if (matches) {
	return unquotedUrl
	}
	}

This excludes url(value)s that uses aliases from being rebased. Then that was rebased by UrlRewritePostcssPlugin.

vite/packages/vite/src/node/plugins/css.ts

Lines 1522 to 1526 in a33d0c7

	UrlRewritePostcssPlugin({
	resolver: urlResolver,
	deps,
	logger: environment.logger,
	}),

While this works fine in most cases, this is incorrect when the replacement is a relative path (e.g. alias: { '@foo': '../foo' }).

That said, this PR would make the implementation more simple and that was the initial motivation.