Light cookies broke some time between 1.69.2 and 1.70.0

[willeastcott]

Works:
https://launch.playcanvas.com/444422?debug=true&version=1.69.2

Broken:
https://launch.playcanvas.com/444422?debug=true&version=1.70.0

[mvaligursky]

from a quick capture of rendering of the back wall on the left.

correct:

broken:

fragment shader difference (not sure this is the actual issue, but that's the difference I see between captures)

needs more investigation