### 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)

}
		it = _get_next_item(it, true);
	}
	if (!from_item || !to_item) {
		return;
	}
	ItemFrame *from_frame = nullptr;
	int from_line = 0;
	_find_frame(from_item, &from_frame, &from_line);
	if (!from_frame) {
		return;
	}
	ItemFrame *to_frame = nullptr;
	int to_line = 0;
	_find_frame(to_item, &to_frame, &to_line);
	if (!to_frame) {
		return;
	}
	selection.from_line = from_line;
	selection.from_frame = from_frame;
	selection.from_char = 0;
	selection.from_item = from_item;
	selection.to_line = to_line;
	selection.to_frame = to_frame;
	selection.to_char = to_frame->lines[to_line].char_count;
	selection.to_item = to_item;
	selection.active = true;
	queue_redraw();
}
bool RichTextLabel::is_selection_enabled() const {