### 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)

return users.size();
}
NodePath LightmapGIData::get_user_path(int p_user) const {
	ERR_FAIL_INDEX_V(p_user, users.size(), NodePath());
	return users[p_user].path;
}
int32_t LightmapGIData::get_user_sub_instance(int p_user) const {
	ERR_FAIL_INDEX_V(p_user, users.size(), -1);
	return users[p_user].sub_instance;
}
Rect2 LightmapGIData::get_user_lightmap_uv_scale(int p_user) const {
	ERR_FAIL_INDEX_V(p_user, users.size(), Rect2());
	return users[p_user].uv_scale;
}
int LightmapGIData::get_user_lightmap_slice_index(int p_user) const {
	ERR_FAIL_INDEX_V(p_user, users.size(), -1);
	return users[p_user].slice_index;
}
void LightmapGIData::clear_users() {
	users.clear();
}
void LightmapGIData::_set_user_data(const Array &p_data) {
	ERR_FAIL_COND(p_data.is_empty());
	ERR_FAIL_COND((p_data.size() % 4) != 0);
	for (int i = 0; i < p_data.size(); i += 4) {
		add_user(p_data[i + 0], p_data[i + 1], p_data[i + 2], p_data[i + 3]);
	}
}
Array LightmapGIData::_get_user_data() const {