In order for the moisture to get into the rice, it first has to evaporate from your wet phone. so you have moisture evaporating into air, then maybe getting absorbed by a nearby grain of rice.
It seems blindingly obvious to me that if that grain of rice wasn’t there, and instead, there was an air current to carry away the moisture, that would, at the absolute minimum, be just as good, and in reality, almost certainly better.
Edit: I realise this isn’t what you were looking for, but I really think the truth of this matter can simply be inferred from the known behaviours of fluids