Clean up outdated `USE_LIGHT_SHADER_CODE` usage

drivers/gles3/shaders/scene.glsl

@@ -936,7 +936,7 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, bool is_di
 #endif
 		inout vec3 diffuse_light, inout vec3 specular_light) {
 
-#if defined(USE_LIGHT_SHADER_CODE)
+#if defined(LIGHT_CODE_USED)
 	// light is written by the light shader
 
 	highp mat4 model_matrix = world_transform;
@@ -1072,7 +1072,7 @@ void light_compute(vec3 N, vec3 L, vec3 V, float A, vec3 light_color, bool is_di
 	alpha = min(alpha, clamp(1.0 - attenuation, 0.0, 1.0));
 #endif
 
-#endif // USE_LIGHT_SHADER_CODE
+#endif // LIGHT_CODE_USED
 }
 
 float get_omni_spot_attenuation(float distance, float inv_range, float decay) {

drivers/gles3/storage/material_storage.cpp

@@ -1178,7 +1178,6 @@ MaterialStorage::MaterialStorage() {
 		actions.usage_defines["SCREEN_PIXEL_SIZE"] = "@SCREEN_UV";
 		actions.usage_defines["NORMAL"] = "#define NORMAL_USED\n";
 		actions.usage_defines["NORMAL_MAP"] = "#define NORMAL_MAP_USED\n";
-		actions.usage_defines["LIGHT"] = "#define LIGHT_SHADER_CODE_USED\n";
 		actions.usage_defines["SPECULAR_SHININESS"] = "#define SPECULAR_SHININESS_USED\n";
 
 		actions.render_mode_defines["skip_vertex_transform"] = "#define SKIP_TRANSFORM_USED\n";
@@ -1326,9 +1325,6 @@ MaterialStorage::MaterialStorage() {
 		actions.usage_defines["BACKLIGHT"] = "#define LIGHT_BACKLIGHT_USED\n";
 		actions.usage_defines["SCREEN_UV"] = "#define SCREEN_UV_USED\n";
 
-		actions.usage_defines["DIFFUSE_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
-		actions.usage_defines["SPECULAR_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
-
 		actions.usage_defines["FOG"] = "#define CUSTOM_FOG_USED\n";
 		actions.usage_defines["RADIANCE"] = "#define CUSTOM_RADIANCE_USED\n";
 		actions.usage_defines["IRRADIANCE"] = "#define CUSTOM_IRRADIANCE_USED\n";

servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp

@@ -680,9 +680,6 @@ void SceneShaderForwardClustered::init(const String p_defines) {
 		actions.usage_defines["BACKLIGHT"] = "#define LIGHT_BACKLIGHT_USED\n";
 		actions.usage_defines["SCREEN_UV"] = "#define SCREEN_UV_USED\n";
 
-		actions.usage_defines["DIFFUSE_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
-		actions.usage_defines["SPECULAR_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
-
 		actions.usage_defines["FOG"] = "#define CUSTOM_FOG_USED\n";
 		actions.usage_defines["RADIANCE"] = "#define CUSTOM_RADIANCE_USED\n";
 		actions.usage_defines["IRRADIANCE"] = "#define CUSTOM_IRRADIANCE_USED\n";

servers/rendering/renderer_rd/forward_mobile/scene_shader_forward_mobile.cpp

@@ -584,9 +584,6 @@ void SceneShaderForwardMobile::init(const String p_defines) {
 		actions.usage_defines["BACKLIGHT"] = "#define LIGHT_BACKLIGHT_USED\n";
 		actions.usage_defines["SCREEN_UV"] = "#define SCREEN_UV_USED\n";
 
-		actions.usage_defines["DIFFUSE_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
-		actions.usage_defines["SPECULAR_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
-
 		actions.usage_defines["FOG"] = "#define CUSTOM_FOG_USED\n";
 		actions.usage_defines["RADIANCE"] = "#define CUSTOM_RADIANCE_USED\n";
 		actions.usage_defines["IRRADIANCE"] = "#define CUSTOM_IRRADIANCE_USED\n";

servers/rendering/renderer_rd/renderer_canvas_render_rd.cpp

@@ -2579,7 +2579,6 @@ RendererCanvasRenderRD::RendererCanvasRenderRD() {
 		actions.usage_defines["SCREEN_PIXEL_SIZE"] = "@SCREEN_UV";
 		actions.usage_defines["NORMAL"] = "#define NORMAL_USED\n";
 		actions.usage_defines["NORMAL_MAP"] = "#define NORMAL_MAP_USED\n";
-		actions.usage_defines["LIGHT"] = "#define LIGHT_SHADER_CODE_USED\n";
 		actions.usage_defines["SPECULAR_SHININESS"] = "#define SPECULAR_SHININESS_USED\n";
 		actions.usage_defines["POINT_SIZE"] = "#define USE_POINT_SIZE\n";