In my opinion, It really depends on how close u are with the helper and how much trust u have in her. How old is your daughter? If the kid is open with affections, should we seriously prevent them from developing that? Kids are innocent and pure and it’s an act of them showing love and thanks back to their caretakers. If you allow kisses on the cheeks and air kisses, that could also encourage the development of affection with ur daughter not just with ur help, but her overall growing up development.
If you really are not comfortable with your helper giving kisses, just be open about it and tell her in private (not in front of your kid). I’m sure she’ll understand and follow it as part of the rules.
Why are you not comfortable with your helper showing affection to your kids? If you want your helper to help raise your child alongside you, don’t you want someone who loves your kids?