Remove KafkaContainer startup timeout

Removed startup timeout for KafkaContainer.

Author: mshima

generators/spring-cloud/generators/kafka/templates/src/test/java/_package_/config/KafkaTestContainer.java.ejs

@@ -31,7 +31,6 @@ import org.testcontainers.junit.jupiter.Container;
 public interface KafkaTestContainer {
     @Container
     KafkaContainer kafkaContainer = new KafkaContainer("<%- dockerContainers.kafka %>")
-        .withStartupTimeout(Duration.ofMinutes(6))
         .withEnv("KAFKA_LISTENERS", "PLAINTEXT://:9092,BROKER://:9093,CONTROLLER://:9094")
         .withLogConsumer(new Slf4jLogConsumer(LoggerFactory.getLogger(KafkaTestContainer.class)));