### 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)

if (!RSG::light_storage->reflection_probe_renders_shadows(light_storage->reflection_probe_instance_get_probe(p_render_data->reflection_probe))) {
			using_shadows = false;
		}
	} else {
		
		light_storage->update_reflection_probe_buffer(p_render_data, *p_render_data->reflection_probes, p_render_data->scene_data->cam_transform.affine_inverse(), p_render_data->environment);
	}
	uint32_t directional_light_count = 0;
	uint32_t positional_light_count = 0;
	light_storage->update_light_buffers(p_render_data, *p_render_data->lights, p_render_data->scene_data->cam_transform, p_render_data->shadow_atlas, using_shadows, directional_light_count, positional_light_count, p_render_data->directional_light_soft_shadows);
	texture_storage->update_decal_buffer(*p_render_data->decals, p_render_data->scene_data->cam_transform);
	p_render_data->directional_light_count = directional_light_count;
}
void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color &p_default_bg_color) {
	RendererRD::LightStorage *light_storage = RendererRD::LightStorage::get_singleton();
	ERR_FAIL_NULL(p_render_data);
	Ref<RenderSceneBuffersRD> rb = p_render_data->render_buffers;
	ERR_FAIL_COND(rb.is_null());
	Ref<RenderBufferDataForwardMobile> rb_data;
	if (rb->has_custom_data(RB_SCOPE_MOBILE)) {
		
		
		rb_data = rb->get_custom_data(RB_SCOPE_MOBILE);
	}
	bool is_reflection_probe = p_render_data->reflection_probe.is_valid();
	RENDER_TIMESTAMP("Prepare 3D Scene");
	_update_vrs(rb);
	RENDER_TIMESTAMP("Setup 3D Scene");
	/* TODO
	// check if we need motion vectors