add emails copy toggle

app/controllers/templates_preferences_controller.rb

@@ -9,6 +9,7 @@ class TemplatesPreferencesController < ApplicationController
     authorize!(:update, @template)
 
     @template.preferences = @template.preferences.merge(template_params[:preferences])
+    @template.preferences = @template.preferences.reject { |_, v| v.is_a?(String) && v.blank? }
     @template.save!
 
     head :ok
@@ -19,7 +20,16 @@ class TemplatesPreferencesController < ApplicationController
   def template_params
     params.require(:template).permit(
       preferences: %i[bcc_completed request_email_subject request_email_body
-                      documents_copy_email_subject documents_copy_email_body]
-    )
+                      documents_copy_email_subject documents_copy_email_body
+                      documents_copy_email_enabled]
+    ).tap do |attrs|
+      attrs[:preferences] = attrs[:preferences].transform_values do |value|
+        if %w[true false].include?(value)
+          value == 'true'
+        else
+          value
+        end
+      end
+    end
   end
 end