### 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)


const GDScriptParser::DataType *current_data_type = &p_class_node->base_type;
	while (current_data_type && current_data_type->kind == GDScriptParser::DataType::Kind::CLASS) {
		GDScriptParser::ClassNode *current_class_node = current_data_type->class_type;
		if (has_member_name_conflict_in_script_class(p_member_name, current_class_node, p_member_node)) {
			String parent_class_name = current_class_node->fqcn;
			if (current_class_node->identifier != nullptr) {
				parent_class_name = current_class_node->identifier->name;
			}
			push_error(vformat(R"(The member "%s" already exists in parent class %s.)", p_member_name, parent_class_name), p_member_node);
			return ERR_PARSE_ERROR;
		}
		current_data_type = &current_class_node->base_type;
	}
	
	if (current_data_type && current_data_type->kind == GDScriptParser::DataType::Kind::NATIVE) {
		if (current_data_type->native_type != StringName()) {
			return check_native_member_name_conflict(
					p_member_name,
					p_member_node,
					current_data_type->native_type);
		}
	}
	return OK;
}
void GDScriptAnalyzer::get_class_node_current_scope_classes(GDScriptParser::ClassNode *p_node, List<GDScriptParser::ClassNode *> *p_list) {