### 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)

List<Item *>::Element *E = p_from;
	while (E != nullptr) {
		ERR_CONTINUE(E->get()->type != ITEM_FRAME); 
		ItemFrame *frame = static_cast<ItemFrame *>(E->get());
		if (p_reverse_search) {
			for (int i = (int)frame->lines.size() - 1; i >= 0; i--) {
				if (_search_line(frame, i, p_string, -1, p_reverse_search)) {
					return true;
				}
			}
		} else {
			for (int i = 0; i < (int)frame->lines.size(); i++) {
				if (_search_line(frame, i, p_string, 0, p_reverse_search)) {
					return true;
				}
			}
		}
		E = p_reverse_search ? E->prev() : E->next();
	}
	return false;
}
bool RichTextLabel::_search_line(ItemFrame *p_frame, int p_line, const String &p_string, int p_char_idx, bool p_reverse_search) {