### Godot version

4.0 fb10f45

### System information

Windows 10 x64

### Issue description

Behold, empty TileSet editor, with no TileMap node nor bottom button visible:
![image](https://github.com/godotengine/godot/assets/2223172/0f052770-4946-40eb-a790-a995dbe2599c)
Regression from #72277 (most likely, I didn't test)

### Steps to reproduce

1. Add some Node to your scene
2. Add a TileMap as a child
3. Select TileMap
4. Fold its parent in the scene tree
5. Restart the editor
6. The TileMap selection is restored and so is the folded node, resulting in a weird paradox

### Minimal reproduction project

N/A
if (is_visible() && animation->has_selectable_items()) {
		_start_onion_skinning();
	}
}
bool AnimationPlayerEditor::_are_onion_layers_valid() {
	ERR_FAIL_COND_V(!onion.past && !onion.future, false);
	Point2 capture_size = get_tree()->get_root()->get_size();
	return onion.captures.size() == onion.get_needed_capture_count() && onion.capture_size == capture_size;
}
void AnimationPlayerEditor::_allocate_onion_layers() {