Ask confirmation to delete pages from the edit page

We were already doing that when deleting pages from the index page, and
we also ask for confirmation in almost every page in the admin section.

app/components/admin/site_customization/pages/edit_component.html.erb

@@ -7,6 +7,7 @@
     @page,
     text: t("admin.site_customization.pages.index.delete"),
     method: :delete,
+    confirm: true,
     class: "delete"
   ) %>
 <% end %>