### 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 (previous.type != GDScriptTokenizer::Token::NEWLINE) {
							push_error(R"(Expected newline after a standalone annotation.)");
						}
						annotation->apply(this, head);
					} else {
						annotation_stack.push_back(annotation);
					}
				}
				break;
			}
			case GDScriptTokenizer::Token::PASS:
				advance();
				end_statement(R"("pass")");
				break;
			case GDScriptTokenizer::Token::DEDENT:
				class_end = true;
				break;
			default:
				
				make_completion_context(COMPLETION_IDENTIFIER, nullptr);
				push_error(vformat(R"(Unexpected "%s" in class body.)", current.get_name()));
				advance();
				break;
		}
		if (panic_mode) {
			synchronize();
		}
		if (!p_is_multiline) {
			class_end = true;
		}