### 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)


if (expression_type.is_variant() && !is_enum_cast && !is_type_compatible(p_type, value_type, true, p_expression)) {
		push_error(vformat(R"(Cannot %s a value of type "%s" as "%s".)", p_usage, value_type.to_string(), p_type.to_string()), p_expression);
		return;
	}
#ifdef DEBUG_ENABLED
	if (p_type.kind == GDScriptParser::DataType::ENUM && value_type.builtin_type == Variant::INT && !enum_has_value(p_type, p_expression->reduced_value)) {
		parser->push_warning(p_expression, GDScriptWarning::INT_AS_ENUM_WITHOUT_MATCH, p_usage, p_expression->reduced_value.stringify(), p_type.to_string());
	}
#endif
	if (value_type.builtin_type == p_type.builtin_type) {
		p_expression->set_datatype(p_type);
		return;
	}
	Variant converted_to;
	const Variant *converted_from = &p_expression->reduced_value;
	Callable::CallError call_error;
	Variant::construct(p_type.builtin_type, converted_to, &converted_from, 1, call_error);
	if (call_error.error) {
		push_error(vformat(R"(Failed to convert a value of type "%s" to "%s".)", value_type.to_string(), p_type.to_string()), p_expression);
		return;
	}
#ifdef DEBUG_ENABLED
	if (p_type.builtin_type == Variant::INT && value_type.builtin_type == Variant::FLOAT) {
		parser->push_warning(p_expression, GDScriptWarning::NARROWING_CONVERSION);
	}
#endif
	p_expression->reduced_value = converted_to;
	p_expression->set_datatype(p_type);
}
void GDScriptAnalyzer::update_array_literal_element_type(GDScriptParser::ArrayNode *p_array, const GDScriptParser::DataType &p_element_type) {