Make sem environments static assets

[FrostKiwi]

Currently environments are loaded via

immersive-web-emulation-runtime/sem/src/sem.ts

Line 157 in 66b61da

loadEnvironment(json: any) {

and stored here as (plain text) .json
https://github.com/meta-quest/immersive-web-emulation-runtime/tree/main/sem/captures

Whilst correctly lazy loaded as chunks, it throws off package bundle size analysis by thinking this is code and reporting a bloated bundle breakdown. Would be great if this was a static .glb or something.