Fix bubble transparency issues

[keianhzo]

Fixes #4801

I've tracked it down to this PR: mrdoob/three.js#22428 that affects the GLTF material import process. It seems that now the material format for GLTF imported materials is RGBFormat if blend mode is opaque so just enabling the transparency flag doesn't work anymore for imported materials with blend opaque modes, we need to switch to RGBAFormat first. It doesn't make much sense and there is an open issue about it mrdoob/three.js#22598 so we can expect an update that fixes that soon.

In the meantime I've patched that in the Hubs client code explicitly switching to RGBAFormat and also switch to NormalBlending (to make sure it works for all models) while the avatar is transparent. I had to also enable DoubleSided rendering, this shouldn't be necessary but it was failing for some models.

As far as I know this is the only place in the app where we need this patch, I can't think of any other place where we import GLTF models and we want to change their transparency on demand but I might be missing some things.

[netpro2k]

Good digging, makes sense... Will definitely continue to monitor that ThreeJS discussion to see where it lands. Don't really have super strong opinions on it, but the current state feels weird for sure.