### 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)


MethodInfo info;
		StringName script_class = p_base_type.kind == GDScriptParser::DataType::SCRIPT ? p_base_type.script_type->get_class_name() : StringName(GDScript::get_class_static());
		if (ClassDB::get_method_info(script_class, function_name, &info)) {
			return function_signature_from_info(info, r_return_type, r_par_types, r_default_arg_count, r_method_flags);
		}
	}
	if (p_is_constructor) {
		
		r_return_type = p_base_type;
		r_return_type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
		r_return_type.is_meta_type = false;
		return true;
	}
	MethodInfo info;
	if (ClassDB::get_method_info(base_native, function_name, &info)) {
		bool valid = function_signature_from_info(info, r_return_type, r_par_types, r_default_arg_count, r_method_flags);
		if (valid && Engine::get_singleton()->has_singleton(base_native)) {
			r_method_flags.set_flag(METHOD_FLAG_STATIC);
		}
#ifdef DEBUG_ENABLED
		MethodBind *native_method = ClassDB::get_method(base_native, function_name);
		if (native_method && r_native_class) {
			*r_native_class = native_method->get_instance_class();
		}
#endif
		return valid;
	}
	return false;
}
bool GDScriptAnalyzer::function_signature_from_info(const MethodInfo &p_info, GDScriptParser::DataType &r_return_type, List<GDScriptParser::DataType> &r_par_types, int &r_default_arg_count, BitField<MethodFlags> &r_method_flags) {