Setting step for size widget does nothing

## Describe the bug

OS: Arch Linux (6.7.1-zen1-1-zen (64-bit))

Changing the step for a size widget continues to use the default step size for the sliders inside a size widget.

For example,
changing `prefab_latent_v3.ts:15`  to  `size: form.size({step: ##}),` does not actually make the sliders use the overridden step size and continues to use the default.