When using GradingPrimaryTransform the generated GLSL code fails to compile. The actual issue is
inside OCIO (https://github.com/AcademySoftwareFoundation/OpenColorIO/issues/1603).
The reason is that unset clamping values are rendered out as `inf`, which isn't recognizable
by GLSL.
The issue is worked around by defining a default for `inf`.
Reviewed By: brecht
Maniphest Tasks: T96502
Differential Revision: https://developer.blender.org/D14425
51727fe86f