When re-publishing a note with `Undo`, the snackbar should show a `Copy Link` link

### What
During the usual note publishing, the snackbar will show the `Copy Link` link (second 6):

https://user-images.githubusercontent.com/73365754/127851389-926875b7-9fc4-4e33-9a1a-973183a06e1e.MP4

However, if the note is unpublished, and user publishes it with `Undo` action again (see video), there will be no `Copy Link` message (second 16).

I think it's worth showing it in this case too.

### Why
This is important, because the link for a re-published note is a new one, which might not be obvious to the user.

### How
As an alternative to above, I even had an idea of making the note unpublishing a non-undoable action, to avoid the chance of user thinking that their old link will still be valid (cc. @SylvesterWilmott) ?

Start by reproducing the publish, unpublish, and republish-with-Undo flow shown in the issue videos, then trace the note publishing and snackbar handling paths. Done means the republished note's snackbar shows a Copy Link action and the existing publishing behavior remains unchanged.

Written by the indexing model from the issue text.