### 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)

Array ret;
	for (int i = 0; i < users.size(); i++) {
		ret.push_back(users[i].path);
		ret.push_back(users[i].uv_scale);
		ret.push_back(users[i].slice_index);
		ret.push_back(users[i].sub_instance);
	}
	return ret;
}
void LightmapGIData::_set_light_textures_data(const Array &p_data) {
	ERR_FAIL_COND(p_data.is_empty());
	if (p_data.size() == 1) {
		set_light_texture(p_data[0]);
	} else {
		Vector<Ref<Image>> images;
		for (int i = 0; i < p_data.size(); i++) {
			Ref<TextureLayered> texture = p_data[i];
			ERR_FAIL_COND_MSG(texture.is_null(), vformat("Invalid TextureLayered at index %d.", i));
			for (int j = 0; j < texture->get_layers(); j++) {
				images.push_back(texture->get_layer_data(j));
			}
		}
		Ref<Texture2DArray> combined_texture;
		combined_texture.instantiate();
		combined_texture->create_from_images(images);
		set_light_texture(combined_texture);
	}
}
Array LightmapGIData::_get_light_textures_data() const {