### 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)


result.kind = GDScriptParser::DataType::NATIVE;
		Object *obj = p_value;
		if (!obj) {
			return GDScriptParser::DataType();
		}
		result.native_type = obj->get_class_name();
		Ref<Script> scr = p_value; 
		if (scr.is_valid()) {
			result.is_meta_type = true;
		} else {
			result.is_meta_type = false;
			scr = obj->get_script();
		}
		if (scr.is_valid()) {
			Ref<GDScript> gds = scr;
			if (gds.is_valid()) {
				
				
				String script_path = gds->get_script_path();
				Ref<GDScriptParserRef> ref = get_parser_for(script_path);
				if (ref.is_null()) {
					push_error(vformat(R"(Could not find script "%s".)", script_path), p_source);
					GDScriptParser::DataType error_type;
					error_type.kind = GDScriptParser::DataType::VARIANT;
					return error_type;
				}
				Error err = ref->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
				GDScriptParser::ClassNode *found = nullptr;
				if (err == OK) {
					found = ref->get_parser()->find_class(gds->fully_qualified_name);