[2.4] Fix notice in wc_nav_menu_items when endpoint is not set

Fixes #9216

includes/wc-page-functions.php

@@ -163,12 +163,14 @@ function wc_nav_menu_items( $items ) {
 	if ( ! is_user_logged_in() ) {
 		$customer_logout = get_option( 'woocommerce_logout_endpoint', 'customer-logout' );
 
+		if ( ! empty( $customer_logout ) ) {
 			foreach ( $items as $key => $item ) {
 				if ( strstr( $item->url, $customer_logout ) ) {
 					unset( $items[ $key ] );
 				}
 			}
 		}
+	}
 
     return $items;
 }