### 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 (p_cell->children[i] != nullptr) {
			_gen_new_positions_from_octree(p_cell->children[i], p_cell_size, probe_positions, new_probe_positions, positions_used, p_bounds);
		}
	}
}
LightmapGI::BakeError LightmapGI::bake(Node *p_from_node, String p_image_data_path, Lightmapper::BakeStepFunc p_bake_step, void *p_bake_userdata) {
	if (p_image_data_path.is_empty()) {
		if (get_light_data().is_null()) {
			return BAKE_ERROR_NO_SAVE_PATH;
		}
		p_image_data_path = get_light_data()->get_path();
		if (!p_image_data_path.is_resource_file()) {
			return BAKE_ERROR_NO_SAVE_PATH;
		}
	}
	Ref<Lightmapper> lightmapper = Lightmapper::create();
	ERR_FAIL_COND_V(lightmapper.is_null(), BAKE_ERROR_NO_LIGHTMAPPER);
	BakeStepUD bsud;
	bsud.func = p_bake_step;
	bsud.ud = p_bake_userdata;
	bsud.from_percent = 0.2;
	bsud.to_percent = 0.8;
	if (p_bake_step) {
		p_bake_step(0.0, RTR("Finding meshes, lights and probes"), p_bake_userdata, true);
	}
	
	Vector<Lightmapper::MeshData> mesh_data;
	Vector<LightsFound> lights_found;
	Vector<Vector3> probes_found;
	AABB bounds;