### Godot version

v4.0.beta14.official [28a24639c]

### System information

MacOS 12.6.2

### Issue description

Beta 14 throws an error for custom `@icon`, e.g.
```
class_name StateMachine extends Node

@icon("res://assets/icons/state_machine.svg")
```
> Annotation "`@icon`" is not allowed in this level.

In beta 13 and before that worked fine.

### Steps to reproduce

1. Add a custom `@icon` in a custom node script.
2. Error message: Annotation "`@icon`" is not allowed in this level.

There are possibly other errors because a `class_name` node is now not recognized if extended by other classes, but they should resolve if `@icon` is removed.

### Minimal reproduction project

N/A
#include "gdscript_parser.h"
#include "core/config/project_settings.h"
#include "core/io/file_access.h"
#include "core/io/resource_loader.h"
#include "core/math/math_defs.h"
#include "gdscript.h"
#include "scene/main/multiplayer_api.h"
#ifdef DEBUG_ENABLED
#include "core/os/os.h"
#include "core/string/string_builder.h"
#include "gdscript_warning.h"
#include "servers/text_server.h"
#endif 
#ifdef TOOLS_ENABLED
#include "editor/editor_settings.h"
#endif 
static HashMap<StringName, Variant::Type> builtin_types;
Variant::Type GDScriptParser::get_builtin_type(const StringName &p_type) {