### 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)

double val = get_edited_property_value();
	if (angle_in_radians) {
		val = Math::rad_to_deg(val);
	}
	setting = true;
	spin->set_value(val);
	setting = false;
}
void EditorPropertyFloat::_bind_methods() {
}
void EditorPropertyFloat::setup(double p_min, double p_max, double p_step, bool p_hide_slider, bool p_exp_range, bool p_greater, bool p_lesser, const String &p_suffix, bool p_angle_in_radians) {
	angle_in_radians = p_angle_in_radians;
	spin->set_min(p_min);
	spin->set_max(p_max);
	spin->set_step(p_step);
	spin->set_hide_slider(p_hide_slider);
	spin->set_exp_ratio(p_exp_range);
	spin->set_allow_greater(p_greater);
	spin->set_allow_lesser(p_lesser);
	spin->set_suffix(p_suffix);
}
EditorPropertyFloat::EditorPropertyFloat() {
	spin = memnew(EditorSpinSlider);
	spin->set_flat(true);
	add_child(spin);
	add_focusable(spin);
	spin->connect("value_changed", callable_mp(this, &EditorPropertyFloat::_value_changed));
}
void EditorPropertyEasing::_set_read_only(bool p_read_only) {