chore: add alert-triangle icon to confirm modals

ui/core/app/templates/application.hbs

@@ -87,6 +87,7 @@
 <PendingConfirmations as |text accept deny|>
   <Rose::Dialog
     @heading={{t "actions.confirm"}}
+    @icon="alert-triangle"
     @modal={{true}}
     @dismiss={{deny}}
   as |dialog|>