Your wife's name on the application is supposed to be the same as what is on her passport or travel documents - so if her maiden name was on her passport at the time you filed the aps, they should be filled out with that name. If she had already changed her passport to her married name, the applications should be filled out with her married name. Either way it probably doesn't matter a whole lot if you included a copy of your marriage licence, which should show both names anyway.
However, this advice doesn't make sense
it will not affect ur file in any way , you have already been approved plus the immigrant officers are acquainted with mistakes like this and believe if this mistake was a problem they would never have approved the file , dont worry and good luck
Your having been approved as the sponsor has nothing at all to do with the applications your wife has filled out for Permanent Residence, and those are the ones where her name is supposed to be the same as on her travel documents/passport.