### 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
if (!p_can_assign) {
		push_error("Assignment is not allowed inside an expression.");
		return parse_expression(false); 
	}
	if (p_previous_operand == nullptr) {
		return parse_expression(false); 
	}
#ifdef DEBUG_ENABLED
	VariableNode *source_variable = nullptr;
#endif
	switch (p_previous_operand->type) {
		case Node::IDENTIFIER: {
#ifdef DEBUG_ENABLED