### 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 (found) {
				break;
			}
			if (script_class->identifier && script_class->identifier->name == first) {
				result = script_class->get_datatype();
				break;
			}
			if (script_class->members_indices.has(first)) {
				resolve_class_member(script_class, first, p_type);
				GDScriptParser::ClassNode::Member member = script_class->get_member(first);
				switch (member.type) {
					case GDScriptParser::ClassNode::Member::CLASS:
						result = member.get_datatype();
						found = true;
						break;
					case GDScriptParser::ClassNode::Member::ENUM:
						result = member.get_datatype();
						found = true;
						break;
					case GDScriptParser::ClassNode::Member::CONSTANT:
						if (member.get_datatype().is_meta_type) {
							result = member.get_datatype();
							found = true;
							break;
						} else if (Ref<Script>(member.constant->initializer->reduced_value).is_valid()) {
							Ref<GDScript> gdscript = member.constant->initializer->reduced_value;
							if (gdscript.is_valid()) {
								Ref<GDScriptParserRef> ref = get_parser_for(gdscript->get_script_path());
								if (ref->raise_status(GDScriptParserRef::INHERITANCE_SOLVED) != OK) {
									push_error(vformat(R"(Could not parse script from "%s".)", gdscript->get_script_path()), p_type);