### 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)

p_item->parent = current;
	p_item->E = current->subitems.push_back(p_item);
	p_item->index = current_idx++;
	p_item->char_ofs = current_char_ofs;
	if (p_item->type == ITEM_TEXT) {
		ItemText *t = static_cast<ItemText *>(p_item);
		current_char_ofs += t->text.length();
	} else if (p_item->type == ITEM_IMAGE) {
		current_char_ofs++;
	}
	if (p_enter) {
		current = p_item;
	}
	if (p_ensure_newline) {
		Item *from = current_frame->lines[current_frame->lines.size() - 1].from;
		
		if (_find_layout_subitem(from, p_item)) {
			_invalidate_current_line(current_frame);
			current_frame->lines.resize(current_frame->lines.size() + 1);
		}
	}
	if (current_frame->lines[current_frame->lines.size() - 1].from == nullptr) {
		current_frame->lines[current_frame->lines.size() - 1].from = p_item;
	}
	p_item->line = current_frame->lines.size() - 1;
	_invalidate_current_line(current_frame);
	if (fit_content) {