### Godot version

4.1.beta3

### System information

Fedora Workstation 38 - Godot 4.1.beta3 - Vulkan (Forward+)

### Issue description

**This is an issue created by the production team, we're working on it**

Currently, it's impossible to call virtual functions within GDScript.

This currently returns an error:
```gdscript
# a.gd
extends Node

func _process(delta: float) -> void:
	pass
```

```gdscript
# main.gd
extends Node

var my_node: Node = preload("res://a.gd").new()

func _process(delta: float) -> void:
	my_node._process(delta)  # Cannot call virtual function "_process()" because it hasn't been defined.
```

### Steps to reproduce

1. Create a script (`a.gd`) based on `Node` that declares `_process()`;
2. Create a main node;
3. Attach a script to the main node;
4. Initialize a variable with a new `a.gd` instance;
5. Try to run `_process()` on that node;
6. Find out that it returns an error.

### Minimal reproduction project

[virtual_functions.zip (updated)](https://github.com/godotengine/godot/files/11823992/virtual_functions.zip)


return bad_type;
								}
								result = ref->get_parser()->head->get_datatype();
							} else {
								result = make_script_meta_type(member.constant->initializer->reduced_value);
							}
							found = true;
							break;
						}
						[[fallthrough]];
					default:
						push_error(vformat(R"("%s" is a %s but does not contain a type.)", first, member.get_type_name()), p_type);
						return bad_type;
				}
			}
		}
	}
	if (!result.is_set()) {
		push_error(vformat(R"(Could not find type "%s" in the current scope.)", first), p_type);
		return bad_type;
	}
	if (p_type->type_chain.size() > 1) {
		if (result.kind == GDScriptParser::DataType::CLASS) {
			for (int i = 1; i < p_type->type_chain.size(); i++) {
				GDScriptParser::DataType base = result;
				reduce_identifier_from_base(p_type->type_chain[i], &base);
				result = p_type->type_chain[i]->get_datatype();
				if (!result.is_set()) {
					push_error(vformat(R"(Could not find type "%s" under base "%s".)", p_type->type_chain[i]->name, base.to_string()), p_type->type_chain[1]);
					return bad_type;