Add missing routes to make group edits work
6b90ccb9fd changed the routes so that users/groups can be accessed via`/:id`, but the Rails `form_for` method expects to use the `groups#show` path helper for the form action URL. This causes group edits and deletes to fail because the PUT/PATCH/DELETE methods did not exist for `/:id`. This MR adds these methods so that `form_for` continues to work.
Closes#23306
See merge request !6874