Send pretty printed JSON body

This is done so that when we log the body, it is
pretty printed.

Closes: #549

core/runtime/src/main/java/io/quarkiverse/langchain4j/QuarkusJsonCodecFactory.java

@@ -15,6 +15,7 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectWriter;
 import com.fasterxml.jackson.databind.PropertyNamingStrategies;
+import com.fasterxml.jackson.databind.SerializationFeature;
 
 import dev.langchain4j.internal.Json;
 import dev.langchain4j.spi.json.JsonCodecFactory;
@@ -79,7 +80,8 @@ public static class SnakeCaseObjectMapperHolder {
         public static final ObjectMapper MAPPER = Arc.container().instance(ObjectMapper.class).get()
                 .copy()
                 .setPropertyNamingStrategy(PropertyNamingStrategies.SNAKE_CASE)
-                .setSerializationInclusion(JsonInclude.Include.NON_NULL);
+                .setSerializationInclusion(JsonInclude.Include.NON_NULL)
+                .enable(SerializationFeature.INDENT_OUTPUT);
     }
 
 }