FIX: check permalinks for deleted topics

- allow to specify 410 vs 404 in Discourse::NotFound exception
- remove unused `permalink_redirect_or_not_found` which
- handle JS side links to topics via Discourse-Xhr-Redirect mechanism

app/controllers/list_controller.rb

@@ -344,7 +344,7 @@ class ListController < ApplicationController
     parent_category_id = nil
     if parent_slug_or_id.present?
       parent_category_id = Category.query_parent_category(parent_slug_or_id)
-      permalink_redirect_or_not_found && (return) if parent_category_id.blank? && !id
+      raise Discourse::NotFound.new("category not found", check_permalinks: true) if parent_category_id.blank? && !id
     end
 
     @category = Category.query_category(slug_or_id, parent_category_id)
@@ -355,7 +355,7 @@ class ListController < ApplicationController
       (redirect_to category.url, status: 301) && return if category
     end
 
-    permalink_redirect_or_not_found && (return) if !@category
+    raise Discourse::NotFound.new("category not found", check_permalinks: true) if !@category
 
     @description_meta = @category.description_text
     raise Discourse::NotFound unless guardian.can_see?(@category)