Blender Git Loki

Fix T87801: Eevee ambient occlusion is incorrect on M1 macMini

The issue was caused by `textureSize()` returning the size of the level 0
even when the min texture level is higher than 0.

Using a uniform to pass the correct size fixes the issue.

This issue also affected the downsampling of radiance for reflections and
refractions.

This does not affect anything other than the recusive downsampling shaders.