test: adds missing import

Author: JasonTheAdams

tests/unit/Results/DTO/GenerativeAiResultTest.php

@@ -6,6 +6,7 @@
 
 use PHPUnit\Framework\TestCase;
 use WordPress\AiClient\Files\DTO\File;
+use WordPress\AiClient\Messages\DTO\Message;
 use WordPress\AiClient\Messages\DTO\MessagePart;
 use WordPress\AiClient\Messages\DTO\ModelMessage;
 use WordPress\AiClient\Messages\Enums\MessagePartTypeEnum;