### 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)

String txt;
	ERR_FAIL_COND_V(p_frame == nullptr, txt);
	ERR_FAIL_COND_V(p_line < 0 || p_line >= (int)p_frame->lines.size(), txt);
	Line &l = p_frame->lines[p_line];
	Item *it_to = (p_line + 1 < (int)p_frame->lines.size()) ? p_frame->lines[p_line + 1].from : nullptr;
	int end_idx = 0;
	if (it_to != nullptr) {
		end_idx = it_to->index;
	} else {
		for (Item *it = l.from; it; it = _get_next_item(it)) {
			end_idx = it->index + 1;
		}
	}
	for (Item *it = l.from; it && it != it_to; it = _get_next_item(it)) {
		if (it->type == ITEM_TABLE) {
			ItemTable *table = static_cast<ItemTable *>(it);
			for (Item *E : table->subitems) {
				ERR_CONTINUE(E->type != ITEM_FRAME); 
				ItemFrame *frame = static_cast<ItemFrame *>(E);
				for (int i = 0; i < (int)frame->lines.size(); i++) {
					txt += _get_line_text(frame, i, p_selection);
				}
			}
		}