Update umlaut_services.yml

added getit URL mask so that marcit 856s do not display (perhaps this should be $O/$L holdings?)
@ajones3066, I think we just want the domain in the Regexp, e.g. `!ruby/regexp '/getit\.library\.nyu\.edu`, since logically we don't want to display "Online Access" versions from Primo that circularly take us back to the page we're on. Once you make the change, I'm happy to merge.