### 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)

GeometryInstanceSurfaceDataCache *sdcache = geometry_instance_surface_alloc.alloc();
	sdcache->flags = flags;
	sdcache->shader = p_material->shader_data;
	sdcache->material = p_material;
	sdcache->material_uniform_set = p_material->uniform_set;
	sdcache->surface = mesh_storage->mesh_get_surface(p_mesh, p_surface);
	sdcache->primitive = mesh_storage->mesh_surface_get_primitive(sdcache->surface);
	sdcache->surface_index = p_surface;
	if (ginstance->data->dirty_dependencies) {
		RSG::utilities->base_update_dependency(p_mesh, &ginstance->data->dependency_tracker);
	}
	
	sdcache->shader_shadow = material_shadow->shader_data;
	sdcache->material_uniform_set_shadow = material_shadow->uniform_set;
	sdcache->surface_shadow = surface_shadow ? surface_shadow : sdcache->surface;
	sdcache->owner = ginstance;
	sdcache->next = ginstance->surface_caches;
	ginstance->surface_caches = sdcache;
	
	sdcache->sort.sort_key1 = 0;
	sdcache->sort.sort_key2 = 0;
	sdcache->sort.surface_index = p_surface;
	sdcache->sort.material_id_low = p_material_id & 0x0000FFFF;
	sdcache->sort.material_id_hi = p_material_id >> 16;
	sdcache->sort.shader_id = p_shader_id;
	sdcache->sort.geometry_id = p_mesh.get_local_index();
	
	sdcache->sort.priority = p_material->priority;
}
void RenderForwardMobile::_geometry_instance_add_surface_with_material_chain(GeometryInstanceForwardMobile *ginstance, uint32_t p_surface, SceneShaderForwardMobile::MaterialData *p_material, RID p_mat_src, RID p_mesh) {