### 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)

}
EditorPropertyObjectID::EditorPropertyObjectID() {
	edit = memnew(Button);
	add_child(edit);
	add_focusable(edit);
	edit->set_text_overrun_behavior(TextServer::OVERRUN_TRIM_ELLIPSIS);
	edit->connect("pressed", callable_mp(this, &EditorPropertyObjectID::_edit_pressed));
}
void EditorPropertySignal::_edit_pressed() {
	Signal signal = get_edited_property_value();
	emit_signal(SNAME("object_id_selected"), get_edited_property(), signal.get_object_id());
}
void EditorPropertySignal::update_property() {
	String type = base_type;
	Signal signal = get_edited_property_value();
	edit->set_text("Signal: " + signal.get_name());
	edit->set_disabled(false);
	edit->set_icon(get_theme_icon(SNAME("Signals"), SNAME("EditorIcons")));
}
void EditorPropertySignal::_bind_methods() {
}
EditorPropertySignal::EditorPropertySignal() {
	edit = memnew(Button);
	add_child(edit);
	add_focusable(edit);
	edit->connect("pressed", callable_mp(this, &EditorPropertySignal::_edit_pressed));
}
void EditorPropertyCallable::update_property() {