Ignore YouTube mix when searching

- We can't extract them properly (at least for now)

Author: mauriciocolli

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

@@ -110,7 +110,8 @@ public InfoItemSearchCollector search(String query, int page, String languageCod
                 collector.commit(new YoutubeStreamInfoItemExtractor(el));
             } else if ((el = item.select("div[class*=\"yt-lockup-channel\"]").first()) != null) {
                 collector.commit(new YoutubeChannelInfoItemExtractor(el));
-            } else if ((el = item.select("div[class*=\"yt-lockup-playlist\"]").first()) != null) {
+            } else if ((el = item.select("div[class*=\"yt-lockup-playlist\"]").first()) != null &&
+                    item.select(".yt-pl-icon-mix").isEmpty()) {
                 collector.commit(new YoutubePlaylistInfoItemExtractor(el));
             } else {
                 // noinspection ConstantConditions