Merge pull request #18273 from Godmartinz/fix-null-assignee-bug-in-checkoutable

Refactor `assignee` in Checkoutable to accept null

Author: snipe

app/Models/Checkoutable.php

@@ -13,7 +13,7 @@ public function __construct(
         public string $name,
         public string $type,
         public object $acceptance,
-        public object $assignee,
+        public readonly User|Asset|Location|null $assignee,
         public readonly string $plain_text_category,
         public readonly string $plain_text_model,
         public readonly string $plain_text_name,