### 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)

bool is_grabbing = false;
	for (int i = 0; i < 3; i++) {
		is_grabbing |= euler[i]->is_grabbing();
	}
	return is_grabbing;
}
void EditorPropertyQuaternion::update_property() {
	Quaternion val = get_edited_property_value();
	setting = true;
	spin[0]->set_value(val.x);
	spin[1]->set_value(val.y);
	spin[2]->set_value(val.z);
	spin[3]->set_value(val.w);
	if (!is_grabbing_euler()) {
		Vector3 v = val.normalized().get_euler();
		edit_euler.x = Math::rad_to_deg(v.x);
		edit_euler.y = Math::rad_to_deg(v.y);
		edit_euler.z = Math::rad_to_deg(v.z);
		euler[0]->set_value(edit_euler.x);
		euler[1]->set_value(edit_euler.y);
		euler[2]->set_value(edit_euler.z);
	}
	setting = false;
}
void EditorPropertyQuaternion::_warning_pressed() {