fix: [authkey:add] Make sure to default to expiration=0 if not provided

src/Model/Table/AuthKeysTable.php

@@ -29,7 +29,7 @@ public function initialize(array $config): void
     public function beforeMarshal(EventInterface $event, ArrayObject $data, ArrayObject $options)
     {
         $data['created'] = time();
-        if (!isset($data['expiration'])) {
+        if (!isset($data['expiration']) || empty($data['expiration'])) {
             $data['expiration'] = 0;
         } else {
             $data['expiration'] = strtotime($data['expiration']);