Can a person suffer mild electrocution if he answers a charging phone with wet hands or sweaty palms?
It wasn't simply the wet hands that killed her, it was also the fact that her body was thoroughly grounded via the bath water and the metallic plumbing of the bathtub. This, coupled with a faulty charger, created a dangerous situation. Only a GFCI/RCD would have saved her.

This is why you don't use cheap no-name chargers. If there's any doubt, plug it into a circuit that's protected by a leakage current detector. This is also why all modern building codes require such protection for all circuits installed near plumbing, as in bathrooms and kitchens.