fix: remove sandbox items from dc record list

oaipmh-core/src/main/java/info/textgrid/middleware/RecordListDelivererDC.java

@@ -142,9 +142,15 @@ public class RecordListDelivererDC extends RecordListDelivererAbstract {
       // All objects!
       recordFilter = query;
     } else {
+      // No sandbox items.
+      QueryBuilder tgFilterSandBox = QueryBuilders.matchPhraseQuery("nearlyPublished", "true");
       // All editions only!
-      recordFilter = QueryBuilders.boolQuery().must(query)
-          .must(QueryBuilders.matchPhraseQuery(this.formatField, this.formatToFilter));
+      QueryBuilder tgEditionsOnly =
+          QueryBuilders.matchPhraseQuery(this.formatField, this.formatToFilter);
+
+      // Compose query.
+      recordFilter =
+          QueryBuilders.boolQuery().must(query).must(tgEditionsOnly).mustNot(tgFilterSandBox);
     }
 
     SearchRequest searchRequest = new SearchRequest(this.oaiEsClient.getEsIndex());