[SoundCloud] Remove trailing , in playlist page urls

Author: Stypox

extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistExtractor.java

@@ -141,8 +141,9 @@ private void computeInitialTracksAndNextPageUrl() throws IOException, Extraction
             }
         }
 
+        nextPageUrlBuilder.setLength(nextPageUrlBuilder.length() - 1); // remove trailing ,
         nextPageUrl = nextPageUrlBuilder.toString();
-        if (nextPageUrl.endsWith("&ids=")) {
+        if (nextPageUrl.endsWith("&ids")) {
             // there are no other videos
             nextPageUrl = "";
         }