Unloading, then Loading cubemap skybox - does not sets it back

[Maksims]

If cubemap asset used as a skybox is unloaded, then loaded back and set as a skybox, the subsequent setting will not result in skybox change, and scene skybox will stay black. While scene.envAtlas - is actually set.

Reproduction project: https://playcanvas.com/editor/scene/2072847
test.js - has the reproduction code