Add testing to the Quarkus AI chapter

[kdubois]

Add a way to test the results of some of the AI calls.

[kdubois]

We can probably just add the new Guardrails feature: https://docs.quarkiverse.io/quarkus-langchain4j/dev/guardrails.html

https://github.com/kdubois/quarkus-langchain4j-samples/blob/main/src/main/java/com/redhat/developers/chatbotwithguardrails/PromptInjectionDetectionService.java