### 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();
	
	scene_state.lightmaps_used = 0;
	for (int i = 0; i < (int)p_lightmaps.size(); i++) {
		if (i >= (int)scene_state.max_lightmaps) {
			break;
		}
		RID lightmap = light_storage->lightmap_instance_get_lightmap(p_lightmaps[i]);
		Basis to_lm = light_storage->lightmap_instance_get_transform(p_lightmaps[i]).basis.inverse() * p_cam_transform.basis;
		to_lm = to_lm.inverse().transposed(); 
		RendererRD::MaterialStorage::store_transform_3x3(to_lm, scene_state.lightmaps[i].normal_xform);
		scene_state.lightmaps[i].exposure_normalization = 1.0;
		if (p_render_data->camera_attributes.is_valid()) {
			float baked_exposure = light_storage->lightmap_get_baked_exposure_normalization(lightmap);
			float enf = RSG::camera_attributes->camera_attributes_get_exposure_normalization_factor(p_render_data->camera_attributes);
			scene_state.lightmaps[i].exposure_normalization = enf / baked_exposure;
		}
		scene_state.lightmap_ids[i] = p_lightmaps[i];
		scene_state.lightmap_has_sh[i] = light_storage->lightmap_uses_spherical_harmonics(lightmap);
		scene_state.lightmaps_used++;
	}
	if (scene_state.lightmaps_used > 0) {
		RD::get_singleton()->buffer_update(scene_state.lightmap_buffer, 0, sizeof(LightmapData) * scene_state.lightmaps_used, scene_state.lightmaps, RD::BARRIER_MASK_RASTER);
	}
}
void RenderForwardMobile::_pre_opaque_render(RenderDataRD *p_render_data) {