Allow featured_image to be set as admin only field

functions.php

<?php
add_filter( 'job_manager_field_editor_js_conf_meta_keys', 'smyles_allow_featured_image_admin_only' );

function smyles_allow_featured_image_admin_only( $js_config ) {

	if ( ! array_key_exists( 'featured_image', $js_config ) || ! array_key_exists( 'disable_fields', $js_config['featured_image'] ) ) {
		return $js_config;
	}

	$found_index = array_search( 'admin_only_0', $js_config['featured_image']['disable_fields'] );

	if ( $found_index ) {
		unset( $js_config['featured_image']['disable_fields'][ $found_index ] );
	}

	return $js_config;
}

//
//
//  OR YOUR CAN USE THIS ONE BELOW, THEY BOTH DO THE SAME THING, ONLY USE ONE OR THE OTHER!
//
//


add_filter( 'job_manager_field_editor_js_conf_meta_keys', 'smyles_allow_featured_image_admin_only' );

/**
 * Allow featured_image to be set as admin only
 */
function smyles_allow_featured_image_admin_only( $config ){
    
    // Make sure admin_only_0 is in disabled fields first (_0 added for any checkboxes)
    if( isset( $config['featured_image'], $config['featured_image']['disable_fields'] ) ){
		// Flip values to array keys so we can unset admin_only_0 and still retain other values
	  	$flipped = array_flip( $config['featured_image']['disable_fields'] );
	    // Remove admin_only_0 from array
	  	unset( $flipped['admin_only_0'] );
	    // Flip back to values
	  	$unflipped = array_flip( $flipped );
	    // Set modified values
	  	$config['featured_image']['disable_fields'] = $unflipped;
    } 
    
    return $config;
    
}