### 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_menu == grid->layer_count) {
		ProjectSettingsEditor::get_singleton()->popup_project_settings(true);
		ProjectSettingsEditor::get_singleton()->set_general_page(basename);
	} else {
		if (grid->value & (1 << p_menu)) {
			grid->value &= ~(1 << p_menu);
		} else {
			grid->value |= (1 << p_menu);
		}
		grid->queue_redraw();
		layers->set_item_checked(layers->get_item_index(p_menu), grid->value & (1 << p_menu));
		_grid_changed(grid->value);
	}
}
void EditorPropertyLayers::_refresh_names() {