Rename sdg_related_list to related_sdg_list

To maintain consistency with the current names in the database with fields:
:related_sdg_type and :related_sdg_id

app/controllers/debates_controller.rb

@@ -55,7 +55,7 @@ class DebatesController < ApplicationController
   private
 
     def debate_params
-      attributes = [:tag_list, :terms_of_service, :sdg_related_list]
+      attributes = [:tag_list, :terms_of_service, :related_sdg_list]
       params.require(:debate).permit(attributes, translation_params(Debate))
     end