fix feed links

app/lib/features/web_feed/extensions/atom.dart

@@ -27,7 +27,7 @@ extension ParseAtomLink on List<AtomLink> {
 }
 
 extension SelectFeedLink on List<FeedLink> {
-  FeedLink? getRelation(FeedLinkRelation relation) {
+  FeedLink? getRelation(FeedLinkRelation? relation) {
     return firstWhereOrNull((link) => link.relation == relation);
   }
 }

app/lib/features/web_feed/presentation/screens/feed_article.dart

@@ -59,7 +59,9 @@ class FeedArticleScreen extends HookConsumerWidget {
               );
 
               final articleLink = useMemoized(
-                () => article.links?.getRelation(FeedLinkRelation.alternate),
+                () =>
+                    article.links?.getRelation(FeedLinkRelation.alternate) ??
+                    article.links?.getRelation(null),
                 [article],
               );