Ensure Bevy's rendering byte usage is little-endian

I got the following response from a wgpu maintainer on Discord:

> fwiw wasm is defined to be little endian, so if you're in the browser it's the browsers job to ensure everything looks like the world is little endian. Furthermore wgsl requires everything to be little-endian. But for all your native host code all bets are off, if you're on BE system it is indeed your job to handle that

The way I interpret that is that I was originally right and it is indeed our responsibility to provide data to wgpu as little endian, not native endian. So `le_bytes` it is, then.

In this case, it might be nice to make a follow-up PR to fix any remaining uses of `ne_bytes` in Bevy.

_Originally posted by @inodentry in https://github.com/bevyengine/bevy/issues/10392#issuecomment-2396819418_