Add cron task to enable resume when indexer is disabled

<?php
/** add facetwp_indexer_cron if it does not exist **/
add_action( 'facetwp_init', function() {
    if ( ! has_action( 'facetwp_indexer_cron' ) ) {
        add_action( 'facetwp_indexer_cron',  'fwp_get_progress' );
    }    
});

function fwp_get_progress() {
    return FWP()->indexer->get_progress();
}