fix: Surface fieldset as a form component

addons/rose/addon/components/rose/form/index.hbs

@@ -20,6 +20,7 @@
     input=(component 'rose/form/input' disabled=this.disabled)
     select=(component 'rose/form/select' disabled=this.disabled)
     textarea=(component 'rose/form/textarea' disabled=this.disabled)
+    fieldset=(component 'rose/form/fieldset')
     actions=(component
       (if this.showEditToggleButton
         'rose/form/actions/edit-toggle'