[media.ccc.de] Add conference title to "recent" kiosk

The "conference_title" field was added upstream recently (see https://github.com/voc/voctoweb/issues/495)

extractor/src/main/java/org/schabi/newpipe/extractor/services/media_ccc/extractors/MediaCCCRecentKioskExtractor.java

@@ -56,7 +56,7 @@ public class MediaCCCRecentKioskExtractor implements StreamInfoItemExtractor {
 
     @Override
     public String getUploaderName() throws ParsingException {
-        return "";
+        return event.getString("conference_title");
     }
 
     @Override