Describe the bug

The Post restored to revision from... message isn't shown when restoring an older revision of a post. The message correctly appears when using the classic editor.

To reproduce
Steps to reproduce the behavior:

1. Publish a post and then make a change to it and save it.
2. Click the Revisions item in the editor sidebar.
3. Navigate to the previous revision and click Restore This Revision.
4. Observe that the revision was restored but there was no success message.

Expected behavior

The Post restored to revision from [date] message should appear, as it does in the classic editor. This is element with index 5 in the post_updated_messages array.