### 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)

String s = get_edited_property_value();
	updating = true;
	if (text->get_text() != s) {
		int caret = text->get_caret_column();
		text->set_text(s);
		text->set_caret_column(caret);
	}
	text->set_editable(!is_read_only());
	updating = false;
}
void EditorPropertyText::set_string_name(bool p_enabled) {
	string_name = p_enabled;
	if (p_enabled) {
		Label *prefix = memnew(Label("&"));
		prefix->set_tooltip_text("StringName");
		prefix->set_mouse_filter(MOUSE_FILTER_STOP);
		text->get_parent()->add_child(prefix);
		text->get_parent()->move_child(prefix, 0);
	}
}
void EditorPropertyText::set_secret(bool p_enabled) {