### 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 err;
			}
			base = ext_parser->get_parser()->head->get_datatype();
		} else {
			if (p_class->extends.is_empty()) {
				push_error("Could not resolve an empty super class path.", p_class);
				return ERR_PARSE_ERROR;
			}
			GDScriptParser::IdentifierNode *id = p_class->extends[extends_index++];
			const StringName &name = id->name;
			base.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
			if (ScriptServer::is_global_class(name)) {
				String base_path = ScriptServer::get_global_class_path(name);
				if (base_path == parser->script_path) {
					base = parser->head->get_datatype();
				} else {
					Ref<GDScriptParserRef> base_parser = get_parser_for(base_path);
					if (base_parser.is_null()) {
						push_error(vformat(R"(Could not resolve super class "%s".)", name), id);
						return ERR_PARSE_ERROR;
					}
					Error err = base_parser->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
					if (err != OK) {
						push_error(vformat(R"(Could not resolve super class inheritance from "%s".)", name), id);
						return err;
					}
					base = base_parser->get_parser()->head->get_datatype();
				}
			} else if (ProjectSettings::get_singleton()->has_autoload(name) && ProjectSettings::get_singleton()->get_autoload(name).is_singleton) {
				const ProjectSettings::AutoloadInfo &info = ProjectSettings::get_singleton()->get_autoload(name);