### 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)

set_current_thread_safe_for_nodes(true);
	_process_line_caches();
	updating.store(false);
	call_deferred(SNAME("thread_end"));
}
void RichTextLabel::_thread_end() {
	set_physics_process_internal(false);
	if (!scroll_visible) {
		vscroll->hide();
	}
	if (is_visible_in_tree()) {
		queue_redraw();
	}
}
void RichTextLabel::_stop_thread() {
	if (threaded) {
		stop_thread.store(true);
		if (task != WorkerThreadPool::INVALID_TASK_ID) {
			WorkerThreadPool::get_singleton()->wait_for_task_completion(task);
			task = WorkerThreadPool::INVALID_TASK_ID;
		}
	}
}
int RichTextLabel::get_pending_paragraphs() const {
	int to_line = main->first_invalid_line.load();
	int lines = main->lines.size();
	return lines - to_line;
}
bool RichTextLabel::is_ready() const {