add: error to response model.

src/Appwrite/Utopia/Response/Model/Migration.php

@@ -85,6 +85,13 @@ class Migration extends Model
                 'default' => [],
                 'example' => [],
             ])
+            ->addRule('error', [
+                'type' => self::TYPE_STRING,
+                'description' => 'A readable error message that occurred during the CSV migration process.',
+                'array' => false,
+                'default' => null,
+                'example' => '',
+            ])
         ;
     }