### 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 (!dialog) {
		dialog = memnew(EditorFileDialog);
		dialog->connect("file_selected", callable_mp(this, &EditorPropertyPath::_path_selected));
		dialog->connect("dir_selected", callable_mp(this, &EditorPropertyPath::_path_selected));
		add_child(dialog);
	}
	String full_path = get_edited_property_value();
	dialog->clear_filters();
	if (global) {
		dialog->set_access(EditorFileDialog::ACCESS_FILESYSTEM);
	} else {
		dialog->set_access(EditorFileDialog::ACCESS_RESOURCES);
	}
	if (folder) {
		dialog->set_file_mode(EditorFileDialog::FILE_MODE_OPEN_DIR);
		dialog->set_current_dir(full_path);
	} else {
		dialog->set_file_mode(save_mode ? EditorFileDialog::FILE_MODE_SAVE_FILE : EditorFileDialog::FILE_MODE_OPEN_FILE);
		for (int i = 0; i < extensions.size(); i++) {
			String e = extensions[i].strip_edges();
			if (!e.is_empty()) {
				dialog->add_filter(extensions[i].strip_edges());
			}
		}
		dialog->set_current_path(full_path);
	}
	dialog->popup_file_dialog();
}
void EditorPropertyPath::update_property() {