Sliced Invoices: remove quantity field from frontend views

function.php

add_filter( 'sliced_invoice_line_items_output', 'si20220317_sliced_invoice_line_items_output_custom' );
function si20220317_sliced_invoice_line_items_output_custom( $output ) {
	if ( preg_match_all('#<t[hd] class="qty">(.*?)</t[hd]>#', $output, $matches) ) {
		$patterns = array();
		$replacements = array();
		foreach ( $matches[1] as $match ) {
			$patterns[] = '#<t[hd] class="qty">'.$match.'</t[hd]>#';
			$replacements[] = '';
		}
		$output = preg_replace($patterns, $replacements, $output);
	}
	return $output;
}