Fix uploader url for related streams

src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractor.java

@@ -782,6 +782,11 @@ public class YoutubeStreamExtractor extends StreamExtractor {
                         .select("span").first().text();
             }
 
+            @Override
+            public String getUploaderUrl() throws ParsingException {
+                return ""; // The uploader is not linked
+            }
+
             @Override
             public String getUploadDate() throws ParsingException {
                 return "";