### Godot version

4.0-rc6

### System information

Fedora 37, Mesa Intel ADL GT2

### Issue description

Code that works as expected at runtime fails with Nil references to (assigned) exported vars in the editor:

![tool_global_position_error](https://user-images.githubusercontent.com/364501/222031460-ffb1ecbd-5175-4a42-8470-25285ba5f821.png)


### Steps to reproduce

Try to access the `global_position` of a `Node3D` that's assigned to an exported var.

See that it works at runtime.

See that it errors in the editor with:

> Invalid get index 'global_position' (on base: 'Nil').

### Minimal reproduction project

[tool_test.zip](https://github.com/godotengine/godot/files/10856640/tool_test.zip)

Button *button = Object::cast_to<Button>(p_button);
	Rect2 rect = button->get_screen_rect();
	change_type->reset_size();
	change_type->set_position(rect.get_end() - Vector2(change_type->get_contents_minimum_size().x, 0));
	change_type->popup();
	changing_type_index = p_index;
}
void EditorPropertyDictionary::_add_key_value() {
	
	if (object->get_new_item_key().get_type() == Variant::NIL) {
		return;
	}
	Dictionary dict = object->get_dict().duplicate();
	dict[object->get_new_item_key()] = object->get_new_item_value();
	object->set_new_item_key(Variant());
	object->set_new_item_value(Variant());
	emit_changed(get_edited_property(), dict, "", false);
	update_property();
}
void EditorPropertyDictionary::_change_type_menu(int p_index) {