### Godot version

4.0 beta 17

### System information

Windows 11, Forward+, RTX 4090

### Issue description

In the latest beta, baking LightmapGI has taken a big performance hit. The baking itself might not be the problem, it's the (Re)Importing Assets step for the `.exr` that seems to take all the time.




### Steps to reproduce

I've included a repro project to demonstrate it. Click the `LightmapGI` node and then the `Bake Lightmaps` button.

Before Beta 17:
`Done baking lightmaps in 00:00:01.`

With Beta 17 (and the latest Master branch, just in case):
`Done baking lightmaps in 00:00:08.`



### Minimal reproduction project

[lightmap-regression-repro.zip](https://github.com/godotengine/godot/files/10579835/lightmap-regression-repro.zip)

}
			if (Object::cast_to<DirectionalLight3D>(light)) {
				DirectionalLight3D *l = Object::cast_to<DirectionalLight3D>(light);
				lightmapper->add_directional_light(light->get_bake_mode() == Light3D::BAKE_STATIC, -xf.basis.get_column(Vector3::AXIS_Z).normalized(), linear_color, energy, l->get_param(Light3D::PARAM_SIZE), l->get_param(Light3D::PARAM_SHADOW_BLUR));
			} else if (Object::cast_to<OmniLight3D>(light)) {
				OmniLight3D *l = Object::cast_to<OmniLight3D>(light);
				if (GLOBAL_GET("rendering/lights_and_shadows/use_physical_light_units")) {
					energy *= (1.0 / (Math_PI * 4.0));
				}
				lightmapper->add_omni_light(light->get_bake_mode() == Light3D::BAKE_STATIC, xf.origin, linear_color, energy, l->get_param(Light3D::PARAM_RANGE), l->get_param(Light3D::PARAM_ATTENUATION), l->get_param(Light3D::PARAM_SIZE), l->get_param(Light3D::PARAM_SHADOW_BLUR));
			} else if (Object::cast_to<SpotLight3D>(light)) {
				SpotLight3D *l = Object::cast_to<SpotLight3D>(light);
				if (GLOBAL_GET("rendering/lights_and_shadows/use_physical_light_units")) {
					energy *= (1.0 / Math_PI);
				}
				lightmapper->add_spot_light(light->get_bake_mode() == Light3D::BAKE_STATIC, xf.origin, -xf.basis.get_column(Vector3::AXIS_Z).normalized(), linear_color, energy, l->get_param(Light3D::PARAM_RANGE), l->get_param(Light3D::PARAM_ATTENUATION), l->get_param(Light3D::PARAM_SPOT_ANGLE), l->get_param(Light3D::PARAM_SPOT_ATTENUATION), l->get_param(Light3D::PARAM_SIZE), l->get_param(Light3D::PARAM_SHADOW_BLUR));
			}
		}
		for (int i = 0; i < probes_found.size(); i++) {
			lightmapper->add_probe(probes_found[i]);
		}
	}
	Ref<Image> environment_image;
	Basis environment_transform;
	
	if (environment_mode != ENVIRONMENT_MODE_DISABLED) {
		if (p_bake_step) {
			p_bake_step(4.1, RTR("Preparing Environment"), p_bake_userdata, true);
		}
		environment_transform = get_global_transform().basis;