workaround badly denormalized data in polls

plugins/poll/plugin.rb

@@ -280,7 +280,8 @@ after_initialize do
         User.where(id: user_ids).each do |user|
           user_hash = UserNameSerializer.new(user).serializable_hash
 
-          poll_votes[user.id.to_s][poll_name].each do |option_id|
+          # protect against poorly denormalized data
+          poll_votes.dig(user.id.to_s, poll_name)&.each do |option_id|
             if (params[:option_id])
               next unless option_id == params[:option_id].to_s
             end