Fix wasm build and add ci check

[johanhelsing]

ggrs doesn't currently build for wasm. Adding a check that it doesn't go by unnoticed in the future.

Adapted the setup I use in Matchbox. Not sure if there's a big difference between running on windows contra ubuntu?

[johanhelsing]

Workaround is to add the getrandom js feature yourself, which I think you'll get indirectly through bevy if you use bevy_ggrs.

[gschup]

super useful! thank you :)