Update check for listed license to check for ID existance

Signed-off-by: Gary O'Neall <gary@sourceauditor.com>

Author: goneall

src/main/java/org/spdx/spdxRdfStore/RdfSpdxDocumentModelManager.java

@@ -665,7 +665,7 @@ public Optional<Object> getPropertyValue(String id, String propertyName) throws
 			Property property = model.createProperty(SpdxResourceFactory.propertyNameToUri(propertyName));
 			NodeIterator iter = model.listObjectsOfProperty(idResource, property);
 			if (!iter.hasNext()) {
-				if (isListedLicenseOrException(idResource)) {
+				if (isListedLicenseOrException(idResource) && !this.exists(id)) {
 					// If there is no locally stored property for a listed license or exception
 					// fetch it from listed licenses store
 					return ListedLicenses.getListedLicenses().getLicenseModelStore()

src/test/java/org/spdx/library/model/license/SpdxListedLicenseTest.java

@@ -20,7 +20,6 @@
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.StringWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;