### 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)

if (p_drag_data["type"] != "nodes") {
		return false;
	}
	Array nodes = p_drag_data["nodes"];
	if (nodes.size() != 1) {
		return false;
	}
	Node *dropped_node = get_tree()->get_edited_scene_root()->get_node(nodes[0]);
	ERR_FAIL_NULL_V(dropped_node, false);
	if (valid_types.is_empty()) {
		
		return true;
	}
	for (const StringName &E : valid_types) {
		if (dropped_node->is_class(E) ||
				EditorNode::get_singleton()->is_object_of_custom_type(dropped_node, E)) {
			return true;
		}
	}
	return false;
}
void EditorPropertyNodePath::update_property() {