SimpleLoggerAdvisor should allow JSON formatting

[michaelisvy]

I am using a SimpleLoggerAdvisor as follows:

public BookRecommendationService(ChatClient.Builder builder) {
        this.chatClient = builder.defaultAdvisors(new SimpleLoggerAdvisor()).build();
 }

It works well, except that the JSON snippets in the logs are heard to read:

2024-09-15T22:16:35.519+08:00 DEBUG 28615 --- [spring-ai-samples2] [           main] o.s.a.c.c.advisor.SimpleLoggerAdvisor    : response: {"result":{"output":{"messageType":"ASSISTANT",
"metadata":{"refusal":"","finishReason":"STOP","index":0,"id":"chatcmpl-A7kLD5Ez8836Wq9a6RKfqh7d3PJYv","role":"ASSISTANT","messageType":"ASSISTANT"},
"toolCalls":[],"content":"{\n  \"author\": \"Bonnie Garmus\",\n  \"title\": \"Lessons in Chemistry\"\n}"},"metadata":
{"contentFilterMetadata":null,"finishReason":"STOP"}},`...

It would be nice if there was a way to format the JSON snippets properly in the logs, so it would be more readable and also would not display the '\n' instructions.

Thanks again for the great work!