OO-2980: expand the citation xml metadata if the user want to edit them

src/main/java/org/olat/modules/portfolio/ui/media/CollectCitationMediaController.java

 /**
+
  * <a href="http://www.openolat.org">
  * OpenOLAT - Online Learning and Training</a><br>
  * <p>
@@ -112,6 +113,10 @@ public class CollectCitationMediaController extends FormBasicController implemen
 		businessPath = media.getBusinessPath();
 		mediaReference = media;
 		
+		if(StringHelper.containsNonWhitespace(mediaReference.getMetadataXml())) {
+			citation = (CitationXml)MetadataXStream.get().fromXML(mediaReference.getMetadataXml());
+		}
+		
 		List<Category> categoryList = portfolioService.getCategories(media);
 		for(Category category:categoryList) {
 			categories.put(category.getName(), category.getName());