Adf 558 display only one title in issn search

https://issues.unige.ch/browse/AOU-558

AoU-ResourceServerCommon/src/main/java/ch/unige/aou/service/metadata/MetadataExtractorV2.java

@@ -455,8 +455,8 @@ public class MetadataExtractorV2 extends MetadataExtractor {
   @Override
   public void setISSN(Object depositDocObj, String value) {
     DepositDoc depositDoc = (DepositDoc) depositDocObj;
-    if (depositDoc.getContainer() == null){
-      depositDoc.setContainer(new Container());
+    if (depositDoc.getIdentifiers() == null){
+      depositDoc.setIdentifiers(new DepositIdentifiers());
     }
     depositDoc.getIdentifiers().setIssn(value);
   }