Fix the "hide snippet" button

[jofwu]

Current "hide snippet" button does nothing.

(Not sure what it's supposed to do?)

[m-strzelczyk]

It was meant to be useful if we had some kind of snippet playlist. Currently however, snippets are visible only in 2 places: audio editor page and next to an entry if they are linked to it.

I'm honestly not sure if we want to hide the snippet from the world if it's linked to visible entry?
There's no point in hiding the snippet from audio editor page for non-staff users, because then they can just recreate it.