### 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)

base_node = Object::cast_to<Node>(get_edited_object());
		if (!base_node) {
			
			if (EditorNode::get_singleton()->get_editor_selection_history()->get_path_size() > 0) {
				Object *base = ObjectDB::get_instance(EditorNode::get_singleton()->get_editor_selection_history()->get_path_object(0));
				if (base) {
					base_node = Object::cast_to<Node>(base);
				}
			}
		}
	}
	if (!base_node && get_edited_object()->has_method("get_root_path")) {
		base_node = Object::cast_to<Node>(get_edited_object()->call("get_root_path"));
	}
	if (!base_node && Object::cast_to<RefCounted>(get_edited_object())) {
		Node *to_node = get_node(p_path);
		ERR_FAIL_COND(!to_node);
		path = get_tree()->get_edited_scene_root()->get_path_to(to_node);
	}
	if (base_node) { 
		path = base_node->get_path().rel_path_to(p_path);
	}
	if (pointer_mode && base_node) {
		emit_changed(_get_meta_pointer_property(), path);
	} else {
		emit_changed(get_edited_property(), path);
	}
	update_property();
}
void EditorPropertyNodePath::_node_assign() {