BIS-772: Fixing "Experiment has not been fetched" for exports.

server-application-server/source/java/ch/ethz/sis/openbis/generic/server/asapi/v3/executor/exporter/EntitiesFinder.java

@@ -139,7 +139,9 @@ class EntitiesFinder
         final List<DataSetPermId> dataSetPermIds = permIds.stream().map(DataSetPermId::new)
                 .collect(Collectors.toList());
         final DataSetFetchOptions fetchOptions = new DataSetFetchOptions();
-        fetchOptions.withSample().withContainer();
+        final SampleFetchOptions sampleFetchOptions = fetchOptions.withSample();
+        sampleFetchOptions.withContainer();
+        sampleFetchOptions.withExperiment().withProperties();
         fetchOptions.withExperiment().withProject().withSpace();
         fetchOptions.withType().withPropertyAssignments().withPropertyType();
         fetchOptions.withProperties();