### 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)

Item *item = p_item;
	float margin = 0.0;
	while (item) {
		if (item->type == ITEM_INDENT) {
			Ref<Font> font = p_base_font;
			int font_size = p_base_font_size;
			ItemFont *font_it = _find_font(item);
			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;