### 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_node && member_node->type != GDScriptParser::Node::ANNOTATION) {
			
			for (GDScriptParser::AnnotationNode *&E : member_node->annotations) {
				if (E->name == SNAME("@warning_ignore")) {
					resolve_annotation(E);
					E->apply(parser, member.variable);
				}
			}
			for (GDScriptWarning::Code ignored_warning : member_node->ignored_warnings) {
				parser->ignored_warnings.insert(ignored_warning);
			}
		}
#endif
		switch (member.type) {
			case GDScriptParser::ClassNode::Member::VARIABLE: {
				bool previous_static_context = static_context;
				static_context = member.variable->is_static;
				check_class_member_name_conflict(p_class, member.variable->identifier->name, member.variable);
				member.variable->set_datatype(resolving_datatype);
				resolve_variable(member.variable, false);
				
				for (GDScriptParser::AnnotationNode *&E : member.variable->annotations) {
					if (E->name != SNAME("@warning_ignore")) {
						resolve_annotation(E);
						E->apply(parser, member.variable);
					}
				}
				static_context = previous_static_context;
#ifdef DEBUG_ENABLED
				if (member.variable->exported && member.variable->onready) {