Fix removing an option for legislation questions

We were allowing the `_destroy` field for translations, but not for the
options themselves.

app/controllers/admin/legislation/questions_controller.rb

@@ -47,7 +47,9 @@ class Admin::Legislation::QuestionsController < Admin::Legislation::BaseControll
     def question_params
       params.require(:legislation_question).permit(
         translation_params(::Legislation::Question),
-        question_options_attributes: [:id, translation_params(::Legislation::QuestionOption)])
+        question_options_attributes: [:id, :_destroy,
+                                      translation_params(::Legislation::QuestionOption)]
+      )
     end
 
     def resource