Congratulations on your new puppy !!! I have to say....Weird on the toes ! Growing up back east...we had a cat that was double pawed...it was a good traite in cats but I don't know what to say about a yorkie with an extra toepad with 2 nails....Wish I could see a picture....
I guess you can expect she'll have really great traction with the extra ?
If it poses no health threat and you are keeping her.... then I would just not worry about it.