### 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)


ERR_FAIL_NULL(p_identifier);
	p_identifier->set_datatype(p_identifier_datatype);
	Error err = OK;
	Ref<GDScript> scr = GDScriptCache::get_shallow_script(p_identifier_datatype.script_path, err);
	if (err) {
		push_error(vformat(R"(Error while getting cache for script "%s".)", p_identifier_datatype.script_path), p_identifier);
		return;
	}
	p_identifier->reduced_value = scr->find_class(p_identifier_datatype.class_type->fqcn);
	p_identifier->is_constant = true;
}
void GDScriptAnalyzer::reduce_identifier_from_base(GDScriptParser::IdentifierNode *p_identifier, GDScriptParser::DataType *p_base) {
	if (!p_identifier->get_datatype().has_no_type()) {
		return;
	}
	GDScriptParser::DataType base;
	if (p_base == nullptr) {
		base = type_from_metatype(parser->current_class->get_datatype());
	} else {
		base = *p_base;
	}
	StringName name = p_identifier->name;
	if (base.kind == GDScriptParser::DataType::ENUM) {
		if (base.is_meta_type) {
			if (base.enum_values.has(name)) {