### 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 (p_node != p_owner && p_node->get_owner() && p_node->get_owner() != p_owner && !p_owner->is_editable_instance(p_node->get_owner())) {
		return OK;
	}
	List<MethodInfo> _signals;
	p_node->get_signal_list(&_signals);
	_signals.sort();
	
	
	for (const MethodInfo &E : _signals) {
		List<Node::Connection> conns;
		p_node->get_signal_connection_list(E.name, &conns);
		conns.sort();
		for (const Node::Connection &F : conns) {
			const Node::Connection &c = F;
			if (!(c.flags & CONNECT_PERSIST)) { 
				continue;
			}
			
			
			Node *target = Object::cast_to<Node>(c.callable.get_object());
			if (!target) {
				continue;
			}
			Vector<Variant> binds;
			int unbinds = 0;
			Callable base_callable;
			if (c.callable.is_custom()) {
				CallableCustomBind *ccb = dynamic_cast<CallableCustomBind *>(c.callable.get_custom());