### Godot version

4.0 rc1

### System information

Windows 11, GTX 1080Ti, Vulkan

### Issue description

Automplete can't find any variables and methods on custom classes when the nodes are loaded with `@onready`:

simple_rotate.gd:
```gdscript
extends Node2D
class_name SimpleRotate

@export var shouldRotate : bool = true
```

machine.gd:
```gdscript
@onready var wheel1 : SimpleRotate = $Wheel

func start_motor():
	wheel1.sho... # Doesn't autocomplete, it can't find shouldRotate 
```

If I add another cast like below, autocomplete does work:
machine.gd:
```gdscript
@onready var wheel1 : SimpleRotate = $Wheel as SimpleRotate

func start_motor():
	wheel1.shouldRotate = true # Autocomplete works
```

To make things even weirder, it does work if I make Wheel into a unique name and access it using %:
machine.gd:
```gdscript
@onready var wheel1 : SimpleRotate = $"%Wheel"

func start_motor():
	wheel1.shouldRotate = true # Autocomplete works
```


### Steps to reproduce

- Create a script with a class_name
- Add that script to a node
- Create another script referencing the node with the type of the script
- Try to let automcomplete find any methods or variables on the script with the class_name
- Notice that it fails

### Minimal reproduction project

N/A
case GDScriptParser::COMPLETION_SUBSCRIPT: {
			const GDScriptParser::SubscriptNode *subscript = static_cast<const GDScriptParser::SubscriptNode *>(completion_context.node);
			GDScriptCompletionIdentifier base;
			if (!_guess_expression_type(completion_context, subscript->base, base)) {
				break;
			}
			_find_identifiers_in_base(base, false, options, 0);
		} break;
		case GDScriptParser::COMPLETION_TYPE_ATTRIBUTE: {
			if (!completion_context.current_class) {
				break;
			}
			const GDScriptParser::TypeNode *type = static_cast<const GDScriptParser::TypeNode *>(completion_context.node);
			bool found = true;
			GDScriptCompletionIdentifier base;
			base.type.kind = GDScriptParser::DataType::CLASS;
			base.type.type_source = GDScriptParser::DataType::INFERRED;
			base.type.is_constant = true;
			base.type.class_type = completion_context.current_class;
			base.value = completion_context.base;
			for (int i = 0; i < completion_context.current_argument; i++) {
				GDScriptCompletionIdentifier ci;
				if (!_guess_identifier_type_from_base(completion_context, base, type->type_chain[i]->name, ci)) {
					found = false;
					break;
				}
				base = ci;
			}
			
			if (found) {