Removed the parallax invert flags and instead all the materials assume displacement is always specified as heightmaps.
Updated property naming, tooltips, and shader variable names to reflect this.
Updated ParallaxMapping.azsli to treat depthOffset as an offset in depth value rather than an offset in height value, so it matches the fact that ParallaxMapping.azsli always operates in depth values rather than height values.
Added new input attachment to the fullscreen reflection pass to receive the "ambient" gbuffer.
Added diffuse and specular occlusion to the Skin material type; it was missing before.
ATOM-14040 Add Support for Cavity Maps
Testing:
AtomSampleViewer automation, with updates that will be submitted in that repo.
Manual testing in Material Editor.
Built all AtomTest assets and opened a few test levels, with updates that will be submitted in that repo.
Made local copies of the occlusion test materials and changed replaced the material types with EnhancedPBR and Skin, and got identical results (with clear coat disabled since it works different in EnhancedPBR and is absent in Skin).