### 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)

uint64_t last_scene_shadow_pass = light_storage->light_instance_get_shadow_pass(p_light);
		if (last_scene_shadow_pass != get_scene_pass()) {
			light_storage->light_instance_set_directional_rect(p_light, light_storage->get_directional_shadow_rect());
			light_storage->directional_shadow_increase_current_light();
			light_storage->light_instance_set_shadow_pass(p_light, get_scene_pass());
		}
		use_pancake = light_storage->light_get_param(base, RS::LIGHT_PARAM_SHADOW_PANCAKE_SIZE) > 0;
		light_projection = light_storage->light_instance_get_shadow_camera(p_light, p_pass);
		light_transform = light_storage->light_instance_get_shadow_transform(p_light, p_pass);
		atlas_rect = light_storage->light_instance_get_directional_rect(p_light);
		if (light_storage->light_directional_get_shadow_mode(base) == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS) {
			atlas_rect.size.width /= 2;
			atlas_rect.size.height /= 2;
			if (p_pass == 1) {
				atlas_rect.position.x += atlas_rect.size.width;
			} else if (p_pass == 2) {
				atlas_rect.position.y += atlas_rect.size.height;
			} else if (p_pass == 3) {
				atlas_rect.position += atlas_rect.size;
			}
		} else if (light_storage->light_directional_get_shadow_mode(base) == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS) {
			atlas_rect.size.height /= 2;
			if (p_pass == 0) {
			} else {
				atlas_rect.position.y += atlas_rect.size.height;
			}
		}
		float directional_shadow_size = light_storage->directional_shadow_get_size();
		Rect2 atlas_rect_norm = atlas_rect;