feat(PointCloud): increase range of picking to u32

[HoloTheDrunk]

Description

Change the picking IDs from u16 to u32.

Motivation and Context

Effectively eliminates the possibility of not having enough IDs to perform picking until GPUs start having 32GB+ of VRAM. Tested on Firefox 123.0 (64-bit) on Ubuntu Linux 22.04.4 LTS x86_64

[HoloTheDrunk]

I don't know where the functional test errors are coming from, I can't replicate them locally so I'm guessing (hoping) it's a toolchain problem and not on my end