[YouTube] Fix NPE when getting channel header for videos channel tab

Author: AudricV

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

@@ -336,8 +336,7 @@ public String getDescription() throws ParsingException {
                 }
             }
 
-            // The description is cut and the original one can be only accessed from the About tab
-            return jsonResponse.getObject("title")
+            return jsonResponse.getObject(METADATA)
                     .getObject("channelMetadataRenderer")
                     .getString("description");
         } catch (final Exception e) {
@@ -432,7 +431,8 @@ private List<ListLinkHandler> getTabsForNonAgeRestrictedChannels() throws Parsin
                                         channelId,
                                         ChannelTabs.VIDEOS,
                                         (service, linkHandler) -> new VideosTabExtractor(
-                                                service, linkHandler, tabRenderer, name, id, url)));
+                                                service, linkHandler, tabRenderer, channelHeader,
+                                                name, id, url)));
 
                                 break;
                             case "shorts":

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

@@ -60,7 +60,7 @@ public class YoutubeChannelTabExtractor extends ChannelTabExtractor {
     @Nullable
     private String visitorData;
     @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
-    private Optional<YoutubeChannelHelper.ChannelHeader> channelHeader;
+    protected Optional<YoutubeChannelHelper.ChannelHeader> channelHeader;
 
     public YoutubeChannelTabExtractor(final StreamingService service,
                                       final ListLinkHandler linkHandler) {
@@ -450,20 +450,24 @@ private Page getNextPageFrom(final JsonObject continuations,
      */
     public static final class VideosTabExtractor extends YoutubeChannelTabExtractor {
         private final JsonObject tabRenderer;
-        private final String channelName;
         private final String channelId;
+        private final String channelName;
         private final String channelUrl;
 
         VideosTabExtractor(final StreamingService service,
                            final ListLinkHandler linkHandler,
                            final JsonObject tabRenderer,
+                           @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
+                           final Optional<YoutubeChannelHelper.ChannelHeader> channelHeader,
                            final String channelName,
                            final String channelId,
                            final String channelUrl) {
             super(service, linkHandler);
+            this.channelHeader = channelHeader;
+
             this.tabRenderer = tabRenderer;
-            this.channelName = channelName;
             this.channelId = channelId;
+            this.channelName = channelName;
             this.channelUrl = channelUrl;
         }