Bug 13613: (Bug 22744 follow-up) Remove js handling for 'none'

Bug 13613: (Bug 22744 follow-up) Remove js handling for 'none'

There was a function and a set of onclick events to handle the 'Do not notify'
checkboxes.

Those have been removed, so should this code

To test:
1 - Sign in to opac
2 - Click on 'your messaging' tab from 'your account'
3 - Check/uncheck some boxes
4 - Note error in the console:
    Uncaught TypeError: document.opacmessaging.none2 is undefined
5 - Apply patch
6 - repeat
7 - no more error

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>