Animals feel their surroundings w/whiskers...especially cats. Since dogs do not go out on their own in the dark, it should be ok. Unless they're going blind...they need those whiskers to 'feel' their surroundings.
For Yorkies & other dog breeds that have a growing coat/hair, it's kind of difficult to get a short cut on the face/ muzzle area w/out cutting the whiskers. If the dog was losing his/her eye sight, I would leave the muzzle area longer, save those whiskers.
This is an interesting article about dog whiskers:
Should you trim your dog’s whiskers? | Humans for Dogs