[YouTube] Correctly set uploaderUrl for lockup content type items

Fixes an issue, where the uploader URL for related items would be incorrect,
due to the `YoutubeChannelLinkHandlerFactory.getUrl` expecting the id with a
`channel/` prefix. However, the `browseId` used to extract the channel id is
missing this prefix.

Ref: TeamNewPipe#1320

Author: FineFindus

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamInfoItemLockupExtractor.java

@@ -191,7 +191,7 @@ public String getUploaderUrl() throws ParsingException {
         if (isNullOrEmpty(channelId)) {
             throw new ParsingException("Could not get uploader url");
         }
-        return YoutubeChannelLinkHandlerFactory.getInstance().getUrl(channelId);
+        return YoutubeChannelLinkHandlerFactory.getInstance().getUrl("channel/" + channelId);
     }
 
     @Nonnull