### 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)

updating_scroll = true;
	float total_height = p_total_height;
	bool exceeds = p_total_height > p_ctrl_height && scroll_active;
	if (exceeds != scroll_visible) {
		if (exceeds) {
			scroll_visible = true;
			scroll_w = vscroll->get_combined_minimum_size().width;
			vscroll->show();
			vscroll->set_anchor_and_offset(SIDE_LEFT, ANCHOR_END, -scroll_w);
		} else {
			scroll_visible = false;
			scroll_w = 0;
		}
		main->first_resized_line.store(0);
		total_height = 0;
		for (int j = 0; j <= p_idx; j++) {
			total_height = _resize_line(main, j, theme_cache.normal_font, theme_cache.normal_font_size, p_width - scroll_w, total_height);
			main->first_resized_line.store(j);
		}
	}
	vscroll->set_max(total_height);
	vscroll->set_page(p_text_rect_height);
	if (scroll_follow && scroll_following) {
		vscroll->set_value(total_height);
	} else {
		vscroll->set_value(p_old_scroll);
	}
	updating_scroll = false;
	return total_height;
}