### Godot version

4.1.1

### System information

windows 11, mobile renderer

### Issue description

On Mobile Vulkan renderer, the clear color is 50% lighter than expected

See steps to reproduce and Minimal reproduction project below.

The box and background have the same color on Forward+ and compatibility, but not on Mobile
happens also in runtime on exported project, not only in editor preview

Images of the same scene from
compatibility:
![compatibility](https://github.com/godotengine/godot/assets/11915378/a874fa86-c16f-43ef-aed7-c2066b770ac1)
Forward+:
![forward](https://github.com/godotengine/godot/assets/11915378/e416f9a6-dfd4-4c47-bbc2-b552ca58f83c)
Mobile:
![mobile](https://github.com/godotengine/godot/assets/11915378/e28e2db8-f7c3-47e2-8c0a-44ce937c9270)


### Steps to reproduce

 - add a CSGBox3D with "unshaded" shading, and albedo of #545454
 - add environment with Background = Custom color and color of #545454

Box and background are not the same color

### Minimal reproduction project

[bg_color.zip](https://github.com/godotengine/godot/files/12174822/bg_color.zip)

RendererRD::MeshStorage *mesh_storage = RendererRD::MeshStorage::get_singleton();
	bool has_read_screen_alpha = p_material->shader_data->uses_screen_texture || p_material->shader_data->uses_depth_texture || p_material->shader_data->uses_normal_texture;
	bool has_base_alpha = p_material->shader_data->uses_alpha && (!p_material->shader_data->uses_alpha_clip || p_material->shader_data->uses_alpha_antialiasing);
	bool has_blend_alpha = p_material->shader_data->uses_blend_alpha;
	bool has_alpha = has_base_alpha || has_blend_alpha || has_read_screen_alpha;
	uint32_t flags = 0;
	if (p_material->shader_data->uses_sss) {
		flags |= GeometryInstanceSurfaceDataCache::FLAG_USES_SUBSURFACE_SCATTERING;
	}
	if (p_material->shader_data->uses_screen_texture) {
		flags |= GeometryInstanceSurfaceDataCache::FLAG_USES_SCREEN_TEXTURE;
	}
	if (p_material->shader_data->uses_depth_texture) {
		flags |= GeometryInstanceSurfaceDataCache::FLAG_USES_DEPTH_TEXTURE;
	}
	if (p_material->shader_data->uses_normal_texture) {
		flags |= GeometryInstanceSurfaceDataCache::FLAG_USES_NORMAL_TEXTURE;
	}