### 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)

if (p_region.has_area()) {
				item->size.height = p_region.get_size().height * p_width / p_region.get_size().width;
			} else {
				item->size.height = p_image->get_height() * p_width / p_image->get_width();
			}
		}
	} else {
		if (p_height > 0) {
			
			item->size.height = p_height;
			
			if (p_region.has_area()) {
				item->size.width = p_region.get_size().width * p_height / p_region.get_size().height;
			} else {
				item->size.width = p_image->get_width() * p_height / p_image->get_height();
			}
		} else {
			if (p_region.has_area()) {
				
				item->size = p_region.get_size();
			} else {
				
				item->size = p_image->get_size();
			}
		}
	}
	_add_item(item, false);
}
void RichTextLabel::add_newline() {