refactor: ListenerExecutionFailedException 조건 수정

- 메시지 처리 도중 발생한 치명적 예외만 ImmediateAcknowledgeAmqpException를 던진다.

Related: #70

src/main/java/com/modoospace/config/rabbitmq/errorhandler/CustomErrorHandler.java

@@ -4,6 +4,7 @@
 import org.springframework.amqp.AmqpRejectAndDontRequeueException;
 import org.springframework.amqp.ImmediateAcknowledgeAmqpException;
 import org.springframework.amqp.rabbit.listener.FatalExceptionStrategy;
+import org.springframework.amqp.rabbit.support.ListenerExecutionFailedException;
 import org.springframework.util.ErrorHandler;
 
 @RequiredArgsConstructor
@@ -13,7 +14,7 @@ public class CustomErrorHandler implements ErrorHandler {
 
     @Override
     public void handleError(Throwable t) {
-        if (this.exceptionStrategy.isFatal(t)) {
+        if (this.exceptionStrategy.isFatal(t) && t instanceof ListenerExecutionFailedException) {
             throw new ImmediateAcknowledgeAmqpException(
                     "Fatal exception encountered. Retry is futile: " + t.getMessage(), t);
         }