Update JackonAutoConfiguration to apply all http.mappers properties

Previously, only the http.mappers.json-sort-keys property was applied
by JacksonAutoConfiguration. This commit updates it to also apply the
http.mappers.json-pretty-print property as well.

See spring-projects#1919

Author: nicoglp

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration.java

@@ -90,6 +90,9 @@ public ObjectMapper jacksonObjectMapper() {
 				objectMapper.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS,
 						true);
 			}
+			if (this.properties.isJsonPrettyPrint()) {
+				objectMapper.configure(SerializationFeature.INDENT_OUTPUT, true);
+			}
 			return objectMapper;
 		}