### 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)

main = memnew(ItemFrame);
	main->index = 0;
	current = main;
	main->lines.resize(1);
	main->lines[0].from = main;
	main->first_invalid_line.store(0);
	main->first_resized_line.store(0);
	main->first_invalid_font_line.store(0);
	current_frame = main;
	vscroll = memnew(VScrollBar);
	add_child(vscroll, false, INTERNAL_MODE_FRONT);
	vscroll->set_drag_node(String(".."));
	vscroll->set_step(1);
	vscroll->set_anchor_and_offset(SIDE_TOP, ANCHOR_BEGIN, 0);
	vscroll->set_anchor_and_offset(SIDE_BOTTOM, ANCHOR_END, 0);
	vscroll->set_anchor_and_offset(SIDE_RIGHT, ANCHOR_END, 0);
	vscroll->connect("value_changed", callable_mp(this, &RichTextLabel::_scroll_changed));
	vscroll->set_step(1);
	vscroll->hide();
	set_text(p_text);
	updating.store(false);
	validating.store(false);
	stop_thread.store(false);
	set_clip_contents(true);
}
RichTextLabel::~RichTextLabel() {
	_stop_thread();
	memdelete(main);
}