GH-5553 Add missing license header to LMDB explain test

Author: hmottestad

core/sail/lmdb/src/test/java/org/eclipse/rdf4j/sail/lmdb/LmdbExplainIndexRecommendationTest.java

@@ -1,3 +1,13 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Eclipse RDF4J contributors.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *******************************************************************************/
 package org.eclipse.rdf4j.sail.lmdb;
 
 import static org.assertj.core.api.Assertions.assertThat;