### Godot version

v4.1.stable.official [970459615]

### System information

Godot v4.1.stable - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce MX330 (NVIDIA; 30.0.15.1169) - 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz (8 Threads)

### Issue description

Calling `RichTextLabel`'s `select_all` method has no visual indicator, but it must have one. 

### Steps to reproduce

- Add `RichTextLabel` node
- Set `selection_enabled` value to be `true`
- Call `$RichTextLabel.select_all() `method in `_ready`

### Minimal reproduction project

[RichTextLabel_bug.zip](https://github.com/godotengine/godot/files/12098913/RichTextLabel_bug.zip)

Item *item = p_item;
	while (item) {
		if (item->type == ITEM_FGCOLOR) {
			ItemFGColor *color = static_cast<ItemFGColor *>(item);
			return color->color;
		}
		item = item->parent;
	}
	return Color(0, 0, 0, 0);
}
bool RichTextLabel::_find_layout_subitem(Item *from, Item *to) {
	if (from && from != to) {
		if (from->type != ITEM_FONT && from->type != ITEM_COLOR && from->type != ITEM_UNDERLINE && from->type != ITEM_STRIKETHROUGH) {
			return true;
		}
		for (Item *E : from->subitems) {
			bool layout = _find_layout_subitem(E, to);
			if (layout) {
				return true;
			}
		}
	}
	return false;
}
void RichTextLabel::_thread_function(void *p_userdata) {