### 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 (member.variable->setter->parameters.size() > 0) {
						member.variable->setter->parameters[0]->datatype_specifier = member.variable->datatype_specifier;
						member.variable->setter->parameters[0]->set_datatype(member.get_datatype());
					}
					resolve_function_body(member.variable->setter);
				}
			}
		} else if (member.type == GDScriptParser::ClassNode::Member::GROUP) {
			
			resolve_annotation(member.annotation);
			member.annotation->apply(parser, nullptr);
		}
	}
	
	for (int i = 0; i < p_class->members.size(); i++) {
		GDScriptParser::ClassNode::Member member = p_class->members[i];
		if (member.type == GDScriptParser::ClassNode::Member::VARIABLE) {
#ifdef DEBUG_ENABLED
			HashSet<GDScriptWarning::Code> previously_ignored_warnings = parser->ignored_warnings;
			for (GDScriptWarning::Code ignored_warning : member.variable->ignored_warnings) {
				parser->ignored_warnings.insert(ignored_warning);
			}
			if (member.variable->usages == 0 && String(member.variable->identifier->name).begins_with("_")) {
				parser->push_warning(member.variable->identifier, GDScriptWarning::UNUSED_PRIVATE_CLASS_VARIABLE, member.variable->identifier->name);
			}
#endif
			if (member.variable->property == GDScriptParser::VariableNode::PROP_SETGET) {
				GDScriptParser::FunctionNode *getter_function = nullptr;
				GDScriptParser::FunctionNode *setter_function = nullptr;
				bool has_valid_getter = false;