It depends. At like 80kph, you're pretty screwed from the impact alone regardless of the vehicle. At 15kph, both are pretty survivable from an impact perspective. But if your survive the impact, the next question is where do you go? For big, raised, boxy vehicles, the answer is more often "under the car" than for cars with ramping low fronts. Having the weight of the car on you is dangerous by itself, even at 1kph.

Then of course there's the impact of the design on driver visibility and therefore accident frequency, especially if the pedestrian is a child, short, in a wheelchair, etc.

The Prius has better visibility, and thus is unlikely to run into a pedestrian.

A large truck/SUV can’t see anything shorter than like 4 feet that is right in front of it… so it is more likely to kill someone just because it can’t see them.