### 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;
	Item *prev_item = p_item;
	int level = 0;
	while (item) {
		if (item->type == ITEM_LIST) {
			ItemList *list = static_cast<ItemList *>(item);
			ItemFrame *frame = nullptr;
			int line = -1;
			_find_frame(list, &frame, &line);
			int index = 1;
			if (frame != nullptr) {
				for (int i = list->line + 1; i <= prev_item->line && i < (int)frame->lines.size(); i++) {
					if (_find_list_item(frame->lines[i].from) == list) {
						index++;
					}
				}
			}
			r_index.push_back(index);
			r_list.push_back(list);
			prev_item = item;
		}
		level++;
		item = item->parent;
	}
	return level;
}
int RichTextLabel::_find_margin(Item *p_item, const Ref<Font> &p_base_font, int p_base_font_size) {