### 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)


break;
			}
			if (all_is_constant && safe_to_fold) {
				
				Vector<const Variant *> args;
				for (int i = 0; i < p_call->arguments.size(); i++) {
					args.push_back(&(p_call->arguments[i]->reduced_value));
				}
				Callable::CallError err;
				Variant value;
				Variant::construct(builtin_type, value, (const Variant **)args.ptr(), args.size(), err);
				switch (err.error) {
					case Callable::CallError::CALL_ERROR_INVALID_ARGUMENT:
						push_error(vformat(R"(Invalid argument for %s constructor: argument %d should be "%s" but is "%s".)", Variant::get_type_name(builtin_type), err.argument + 1,
										   Variant::get_type_name(Variant::Type(err.expected)), p_call->arguments[err.argument]->get_datatype().to_string()),
								p_call->arguments[err.argument]);
						break;
					case Callable::CallError::CALL_ERROR_INVALID_METHOD: {
						String signature = Variant::get_type_name(builtin_type) + "(";
						for (int i = 0; i < p_call->arguments.size(); i++) {
							if (i > 0) {
								signature += ", ";
							}
							signature += p_call->arguments[i]->get_datatype().to_string();
						}
						signature += ")";
						push_error(vformat(R"(No constructor of "%s" matches the signature "%s".)", Variant::get_type_name(builtin_type), signature), p_call->callee);
					} break;
					case Callable::CallError::CALL_ERROR_TOO_MANY_ARGUMENTS:
						push_error(vformat(R"(Too many arguments for %s constructor. Received %d but expected %d.)", Variant::get_type_name(builtin_type), p_call->arguments.size(), err.expected), p_call);