Absolute / domain-relative path for asset URLs in CSS

@strarsis Apologies, I accidentally copied the wrong snippet! :man_facepalming:

This is the code I meant to copy:

/**
 * Add custom Gutenberg editor CSS and JS assets
 * https://developer.wordpress.org/block-editor/tutorials/javascript/extending-the-block-editor/
 * https://soderlind.no/hide-block-styles-in-gutenberg/
 */
add_action('enqueue_block_editor_assets', function() {
    // NOTE: This won’t apply CSS to block pattern preview iframes
    //       when “bud dev” is running since the CSS is injected,
    //       but it will work in production or after running “bud build”
    bundle('app')->enqueue();
}, 100);