Fix archive open in single-column layout.

Regression was introduced in 16128d6.

Before we always force-closed the current filter,
which always force-closed the current opened chat.

Now we don't touch the filter if it is All Chats already,
so that it's scroll state isn't forgotten. In that case
we have to clear the stack in single-column layout explicitly.

Telegram/SourceFiles/window/window_session_controller.cpp

@@ -1160,6 +1160,8 @@ void SessionController::openFolder(not_null<Data::Folder*> folder) {
 	}
 	if (activeChatsFilterCurrent() != 0) {
 		setActiveChatsFilter(0);
+	} else if (adaptive().isOneColumn()) {
+		clearSectionStack(SectionShow::Way::ClearStack);
 	}
 	closeForum();
 	_openedFolder = folder.get();