[psppno_post slug] instead of permalink

[rizaardiyanto1412]

This is useful if the user in the backend use WordPress, but in the frontend does not.

For example - notification renders https://at.apartmenttherapymedia.com/house-tour/creative-and-eclectic-nyc-rental-on-a-shoestring-budget-37247635

however, the actual Public URL is https://www.apartmenttherapy.com/creative-and-eclectic-nyc-rental-on-a-shoestring-budget-37247635

So the user can set in the notification as https://www.apartmenttherapy.com/[psppno_post slug]