Remove redundant clearing of list

Author: imericxu

app/src/main/java/org/schabi/newpipe/player/playqueue/PlayQueue.java

@@ -476,7 +476,6 @@ public synchronized void unshuffle() {
         final int originIndex = getIndex();
         final PlayQueueItem current = getItem();
 
-        streams.clear();
         streams = backup;
         backup = null;