Fix NameError on ActivityPub::FetchFeaturedCollectionService (#17326)

Related: #16954

app/services/activitypub/fetch_featured_collection_service.rb

@@ -48,6 +48,6 @@ class ActivityPub::FetchFeaturedCollectionService < BaseService
   end
 
   def local_follower
-    @local_follower ||= account.followers.local.without_suspended.first
+    @local_follower ||= @account.followers.local.without_suspended.first
   end
 end