[Atom] Honor shader-debug overrides and trim unused shader dependencies - #20106

TransformColor.azsli includes AcesCcToAcesCg.azsli unconditionally, and that
pulls in Atom/Features/PostProcessing/Aces.azsli: 808 preprocessed lines of
ACES reference transforms. Every shader that calls TransformColor pays for
them whether or not ACEScc is ever selected. For Material Canvas that is
every graph containing a texture, because sample_texture_2d requests the file
for its colour space conversion, and the library is then the single largest
contributor to what azslc parses.

The two ACEScc conversions are now guarded by ENABLE_ACESCC_COLOR_SPACE,
which defaults to 1, so nothing changes unless a pipeline asks. With it off,
conversions to or from ACEScc fall through to the same magenta that any other
unsupported pair already produces below. That is deliberate: visibly wrong
beats quietly approximate. No other colour space is affected, and nothing
else in the material shader path reaches Aces.azsli.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Signed-off-by: Grimwarrior <143121582+Grimwarrior@users.noreply.github.com>

ENABLE_LIGHT_CULLING guards the call sites inside LightCullingTileIterator,
so setting it to 0 is widely assumed to remove the light culling code. It
does not. LightCullingShared.azsli includes NVLC.azsli unconditionally and
the iterator includes that header outside any guard, so about 285 lines
survive the option in every forward shader.

With culling off, Init() compiles down to InitNoCulling() and the only things
still wanted from the header are two sentinel values the iterator compares
against. The #else defines those directly and skips the include.

Note the include order. Atom/Features/PBR/LightingOptions.azsli has to come
first, because it declares ENABLE_LIGHT_CULLING and #if reads an undefined
macro as 0. The original order would have dropped light culling from every
shader in the engine.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Signed-off-by: Grimwarrior <143121582+Grimwarrior@users.noreply.github.com>

…that force it off

The mobile and multi view pipelines define ENABLE_SHADER_DEBUGGING to 0 rather
than 1, so the previous commit left them alone: a pipeline wanting the debug
views compiled out already had that there.

They have the mirror of the same defect. Unconditional means the command line
loses either way, so nothing can turn the debug views back on for these
pipelines, and asking warns about a redefinition rather than doing anything.

Guarding them changes nothing about what is built. The default stays 0, which is
what these pipelines have always compiled, and no pipeline in the tree defines
the macro on the command line today.

With these eight, every definition of ENABLE_SHADER_DEBUGGING in the tree is
guarded -- the twelve pipeline files from the previous commit, these eight, and
the two in ShaderLib that were already written this way.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Signed-off-by: Grimwarrior <143121582+Grimwarrior@users.noreply.github.com>