### 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 name = p_name;
	if (name == "new_item_key") {
		r_ret = new_item_key;
		return true;
	}
	if (name == "new_item_value") {
		r_ret = new_item_value;
		return true;
	}
	if (name.begins_with("indices")) {
		int index = name.get_slicec('/', 1).to_int();
		Variant key = dict.get_key_at_index(index);
		r_ret = dict[key];
		if (r_ret.get_type() == Variant::OBJECT && Object::cast_to<EncodedObjectAsID>(r_ret)) {
			r_ret = Object::cast_to<EncodedObjectAsID>(r_ret)->get_object_id();
		}
		return true;
	}
	return false;
}
void EditorPropertyDictionaryObject::set_dict(const Dictionary &p_dict) {
	dict = p_dict;
}
Dictionary EditorPropertyDictionaryObject::get_dict() {
	return dict;
}
void EditorPropertyDictionaryObject::set_new_item_key(const Variant &p_new_item) {