Fix checkstyle

Author: danielftavares

java-client/src/test/java/co/elastic/clients/json/jackson/JacksonJsonpGeneratorTest.java

@@ -1,6 +1,23 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
 package co.elastic.clients.json.jackson;
 
-import jakarta.json.stream.JsonGenerator;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;