Remove redundant method to set order

It was being incorrectly detected as used in a dangerous send. We can
get rid of the warning by taking advantage of the `has_orders` method
and getting rid of this code.

app/controllers/communities_controller.rb

@@ -1,8 +1,6 @@
 class CommunitiesController < ApplicationController
-  TOPIC_ORDERS = %w[newest most_commented oldest].freeze
-  before_action :set_order, :set_community, :load_topics, :load_participants
-
-  has_orders TOPIC_ORDERS
+  has_orders %w[newest most_commented oldest]
+  before_action :set_community, :load_topics, :load_participants
 
   skip_authorization_check
 
@@ -14,26 +12,18 @@ class CommunitiesController < ApplicationController
 
   private
 
-    def set_order
-      @order = valid_order? ? params[:order] : "newest"
-    end
-
     def set_community
       @community = Community.find(params[:id])
     end
 
     def load_topics
-      @topics = @community.topics.send("sort_by_#{@order}").page(params[:page])
+      @topics = @community.topics.send("sort_by_#{@current_order}").page(params[:page])
     end
 
     def load_participants
       @participants = @community.participants
     end
 
-    def valid_order?
-      params[:order].present? && TOPIC_ORDERS.include?(params[:order])
-    end
-
     def communitable_exists?
       @community.proposal.present? || @community.investment.present?
     end