When WebGL device is lost during the creation, we might get an undefined access

[mvaligursky]

forum thread: https://forum.playcanvas.com/t/after-opening-and-closing-3d-applications-multiple-times-consecutively-the-model-cannot-be-displayed-on-ios17/33374

the actual error:

This seems to take place when the device is lost and the cubemap finishes loading, and we try to prefilter it. The problem is that the device was never successfully created, and so we have some uninitialized data we're trying to access.