This isn't possible to my knowledge. Her heels are below ground because.. that's how VRChat's floor level works. All scaling is done manually within. An animation can check whether or not the avatar’s scale’s been modified and by how much, however VRChat currently does not permit animation-based scaling, at least traditionally with your own toggle. However- this is scaling and not position. You're talking about position. I haven't messed with position, you could always try but make sure you have a backup avatar. It never hurts to try. Back to scaling-- VRCFury can only do asset scaling and not avatar scaling as the scale is now managed through VRChat, more specifically Udon since world creators can restrict the use of avatar scaling. Hope this helps! Give it a shot, try making a toggle that moves her position upwards.

Once you get used to it, you'll almost perfect it with little to no errors first try.