Exclude replies from list timelines (#8683)

* Changed list behaviour

I added the following line to the FeedManager (app/lib/feed_manager.rb) in the push_to_list function:

`return false if status.reply?`

Now all posts that are replies are filtered out, so that now only "genuine" posts are displayed in the list.

This is a first approach to solve issue #5916

* Update feed_manager.rb

As suggested by @Gargron

app/lib/feed_manager.rb

@@ -40,6 +40,7 @@ class FeedManager
   end
 
   def push_to_list(list, status)
+    return false if status.reply? && status.in_reply_to_account_id != status.account_id
     return false unless add_to_feed(:list, list.id, status)
     trim(:list, list.id)
     PushUpdateWorker.perform_async(list.account_id, status.id, "timeline:list:#{list.id}") if push_update_required?("timeline:list:#{list.id}")