### 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 (is_constructor) {
			name = "_init";
		}
		if (script_class->has_member(name)) {
			resolve_class_member(script_class, name, p_identifier);
			GDScriptParser::ClassNode::Member member = script_class->get_member(name);
			switch (member.type) {
				case GDScriptParser::ClassNode::Member::CONSTANT: {
					p_identifier->set_datatype(member.get_datatype());
					p_identifier->is_constant = true;
					p_identifier->reduced_value = member.constant->initializer->reduced_value;
					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
					p_identifier->constant_source = member.constant;
					return;
				}
				case GDScriptParser::ClassNode::Member::ENUM_VALUE: {
					p_identifier->set_datatype(member.get_datatype());
					p_identifier->is_constant = true;
					p_identifier->reduced_value = member.enum_value.value;
					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
					return;
				}
				case GDScriptParser::ClassNode::Member::ENUM: {
					p_identifier->set_datatype(member.get_datatype());
					p_identifier->is_constant = true;
					p_identifier->reduced_value = member.m_enum->dictionary;
					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
					return;
				}