### 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)

const_cast<RichTextLabel *>(this)->_validate_line_caches();
	int total_height = 0;
	int to_line = main->first_invalid_line.load();
	if (to_line) {
		MutexLock lock(main->lines[to_line - 1].text_buf->get_mutex());
		if (theme_cache.line_separation < 0) {
			
			total_height = main->lines[to_line - 1].offset.y + main->lines[to_line - 1].text_buf->get_size().y + (main->lines[to_line - 1].text_buf->get_line_count() - 1) * theme_cache.line_separation;
		} else {
			total_height = main->lines[to_line - 1].offset.y + main->lines[to_line - 1].text_buf->get_size().y + main->lines[to_line - 1].text_buf->get_line_count() * theme_cache.line_separation;
		}
	}
	return total_height;
}
int RichTextLabel::get_content_width() const {
	const_cast<RichTextLabel *>(this)->_validate_line_caches();
	int total_width = 0;
	int to_line = main->first_invalid_line.load();
	for (int i = 0; i < to_line; i++) {
		MutexLock lock(main->lines[i].text_buf->get_mutex());
		total_width = MAX(total_width, main->lines[i].offset.x + main->lines[i].text_buf->get_size().x);
	}
	return total_width;
}
#ifndef 
bool RichTextLabel::_set(const StringName &p_name, const Variant &p_value) {