DEV: Generate correct i18n keys for wizard radio choices (#28370)

If you wizard step has a dash in it, e.g. foo-bar, the wrong i18n key will be inferred for selects. This PR ensures the key is underscored.

app/serializers/wizard_field_choice_serializer.rb

@@ -10,7 +10,7 @@ class WizardFieldChoiceSerializer < ApplicationSerializer
   def i18nkey
     field = object.field
     step = field.step
-    "wizard.step.#{step.id}.fields.#{field.id}.choices.#{id}"
+    "wizard.step.#{step.id}.fields.#{field.id}.choices.#{id}".underscore
   end
 
   def label