Inline background with border-box value will be accidentally stripped

[eiinu]

Basic info:

• Node.js version: v18.17.1
• jsdom version: v23.2.0

Minimal reproduction case

const jsdom = require('jsdom');
const { JSDOM } = jsdom;

const dom = new JSDOM(`<div id="test" style="background: border-box;"></div>`)
const { document } = dom.window
const value = document.querySelector('#test').style.background
console.log(value); // value is '', which is expected to be 'border-box'