fix crash when return null as a related streams collector

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

@@ -188,7 +188,7 @@ public class MediaCCCStreamExtractor extends StreamExtractor {
 
     @Override
     public StreamInfoItemsCollector getRelatedStreams() throws IOException, ExtractionException {
-        return null;
+        return new StreamInfoItemsCollector(getServiceId());
     }
 
     @Override

extractor/src/main/java/org/schabi/newpipe/extractor/utils/ExtractorHelper.java

@@ -30,6 +30,7 @@ public class ExtractorHelper {
     public static List<InfoItem> getRelatedVideosOrLogError(StreamInfo info, StreamExtractor extractor) {
         try {
             InfoItemsCollector<? extends InfoItem, ?> collector = extractor.getRelatedStreams();
+            if(collector == null) return Collections.emptyList();
             info.addAllErrors(collector.getErrors());
 
             //noinspection unchecked