### 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)

}
EditorPropertyPath::EditorPropertyPath() {
	HBoxContainer *path_hb = memnew(HBoxContainer);
	add_child(path_hb);
	path = memnew(LineEdit);
	SET_DRAG_FORWARDING_CDU(path, EditorPropertyPath);
	path->set_structured_text_bidi_override(TextServer::STRUCTURED_TEXT_FILE);
	path_hb->add_child(path);
	path->connect("text_submitted", callable_mp(this, &EditorPropertyPath::_path_selected));
	path->connect("focus_exited", callable_mp(this, &EditorPropertyPath::_path_focus_exited));
	path->set_h_size_flags(SIZE_EXPAND_FILL);
	path_edit = memnew(Button);
	path_edit->set_clip_text(true);
	path_hb->add_child(path_edit);
	add_focusable(path);
	dialog = nullptr;
	path_edit->connect("pressed", callable_mp(this, &EditorPropertyPath::_path_pressed));
}
void EditorPropertyClassName::_set_read_only(bool p_read_only) {
	property->set_disabled(p_read_only);
}
void EditorPropertyClassName::setup(const String &p_base_type, const String &p_selected_type) {
	base_type = p_base_type;
	dialog->set_base_type(base_type);
	selected_type = p_selected_type;
	property->set_text(selected_type);
}
void EditorPropertyClassName::update_property() {