### 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 (changing_type_index < 0) {
		Variant value;
		VariantInternal::initialize(&value, Variant::Type(p_index));
		if (changing_type_index == -1) {
			object->set_new_item_key(value);
		} else {
			object->set_new_item_value(value);
		}
		update_property();
		return;
	}
	Dictionary dict = object->get_dict().duplicate();
	if (p_index < Variant::VARIANT_MAX) {
		Variant value;
		VariantInternal::initialize(&value, Variant::Type(p_index));
		Variant key = dict.get_key_at_index(changing_type_index);
		dict[key] = value;
	} else {
		Variant key = dict.get_key_at_index(changing_type_index);
		dict.erase(key);
	}
	emit_changed(get_edited_property(), dict, "", false);
	update_property();
}
void EditorPropertyDictionary::setup(PropertyHint p_hint) {