### 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::LightStorage *light_storage = RendererRD::LightStorage::get_singleton();
	RendererRD::TextureStorage *texture_storage = RendererRD::TextureStorage::get_singleton();
	p_render_data->cube_shadows.clear();
	p_render_data->shadows.clear();
	p_render_data->directional_shadows.clear();
	Plane camera_plane(-p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z), p_render_data->scene_data->cam_transform.origin);
	float lod_distance_multiplier = p_render_data->scene_data->cam_projection.get_lod_multiplier();
	{
		for (int i = 0; i < p_render_data->render_shadow_count; i++) {
			RID li = p_render_data->render_shadows[i].light;
			RID base = light_storage->light_instance_get_base_light(li);
			if (light_storage->light_get_type(base) == RS::LIGHT_DIRECTIONAL) {
				p_render_data->directional_shadows.push_back(i);
			} else if (light_storage->light_get_type(base) == RS::LIGHT_OMNI && light_storage->light_omni_get_shadow_mode(base) == RS::LIGHT_OMNI_SHADOW_CUBE) {
				p_render_data->cube_shadows.push_back(i);
			} else {
				p_render_data->shadows.push_back(i);
			}
		}