Fix existing attendee format to be only ints or nulls

src/Tickets/Commerce/Attendee.php

@@ -501,6 +501,9 @@ public function upsert( \WP_Post $order, $ticket, array $args = [], ?int $existi
 			$update_args['fields'] = $fields;
 		}
 
+		// No need to update the security code.
+		unset( $update_args['security_code'] );
+
 		/**
 		 * Allow the filtering of the update arguments for attendee.
 		 *

src/Tickets/Commerce/Flag_Actions/Generate_Attendees.php

@@ -123,8 +123,12 @@ public function handle( Status_Interface $new_status, $old_status, \WP_Post $ord
 						'ticket_id' => $ticket->ID,
 						'event_id'  => $ticket->get_event_id(),
 					]
-				)->fields( 'ids' )->all( true ) as $attendee_id
+				)->get_ids( true ) as $attendee_id
 			) {
+				if ( ! is_int( $attendee_id ) || 0 >= $attendee_id ) {
+					$existing[] = null;
+					continue;
+				}
 				$existing[] = $attendee_id;
 			}