fix npe in fetching service by url

Author: yausername

extractor/src/main/java/org/schabi/newpipe/extractor/StreamingService.java

@@ -308,11 +308,11 @@ public final LinkType getLinkTypeByUrl(String url) throws ParsingException {
         LinkHandlerFactory cH = getChannelLHFactory();
         LinkHandlerFactory pH = getPlaylistLHFactory();
 
-        if (sH.acceptUrl(url)) {
+        if (sH != null && sH.acceptUrl(url)) {
             return LinkType.STREAM;
-        } else if (cH.acceptUrl(url)) {
+        } else if (cH != null && cH.acceptUrl(url)) {
             return LinkType.CHANNEL;
-        } else if (pH.acceptUrl(url)) {
+        } else if (pH != null && pH.acceptUrl(url)) {
             return LinkType.PLAYLIST;
         } else {
             return LinkType.NONE;