### 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)

segment = _roman(list_index[i], list_items[i]->capitalize);
		}
		if (rtl) {
			prefix = prefix + segment;
		} else {
			prefix = segment + prefix;
		}
	}
	if (!prefix.is_empty()) {
		Ref<Font> font = theme_cache.normal_font;
		int font_size = theme_cache.normal_font_size;
		ItemFont *font_it = _find_font(l.from);
		if (font_it) {
			if (font_it->font.is_valid()) {
				font = font_it->font;
			}
			if (font_it->font_size > 0) {
				font_size = font_it->font_size;
			}
		}
		ItemFontSize *font_size_it = _find_font_size(l.from);
		if (font_size_it && font_size_it->font_size > 0) {
			font_size = font_size_it->font_size;
		}
		if (rtl) {
			float offx = 0.0f;
			if (!lrtl && p_frame == main) { 
				offx -= scroll_w;
			}
			font->draw_string(ci, p_ofs + Vector2(p_width - l.offset.x + offx, l.text_buf->get_line_ascent(0)), " " + prefix, HORIZONTAL_ALIGNMENT_LEFT, l.offset.x, font_size, _find_color(l.from, p_base_color));