### Godot version

v4.0.beta16.official [518b9e580]

### System information

Windows 10

### Issue description

`RichTextLabel` with `threaded` enabled may crash the game or show the following warning if the node is in another scene:

```
W 0:00:03:0802   test.gd:12 @ load_with_scene(): A Thread object has been re-started without wait_to_finish() having been called on it. Please do so to ensure correct cleanup of the thread.
  <C++ Source>   core/os/thread.cpp:76 @ start()
  <Stack Trace>  test.gd:12 @ load_with_scene()
                 test.gd:6 @ load_items()
                 test.gd:26 @ _on_button_pressed()
```

It may crash the game (without any warning) if it's added directly.

In `v4.0.beta15.official [4fa6edc88]` I was able to reproduce the same warning on my project but I can't reproduce it in the attached MRP. I get a different error and will crash too if the node is added directly:

```
E 0:00:03:0019   remove_from_group: Condition "!E" is true.
  <C++ Source>   scene/main/scene_tree.cpp:157 @ remove_from_group()
```


### Steps to reproduce

Click on the  `Load with scene` or `Load with node` buttons in the attached MRP until it shows a warning/error or crashes. It may take a while.

### Minimal reproduction project

[add_chid_bug_b16.zip](https://github.com/godotengine/godot/files/10521402/add_chid_bug_b16.zip)

if (funcs == nullptr) {
		funcs = hb_font_funcs_create();
		hb_font_funcs_set_font_h_extents_func(funcs, _bmp_get_font_h_extents, nullptr, nullptr);
		hb_font_funcs_set_nominal_glyph_func(funcs, _bmp_get_nominal_glyph, nullptr, nullptr);
		hb_font_funcs_set_glyph_h_advance_func(funcs, _bmp_get_glyph_h_advance, nullptr, nullptr);
		hb_font_funcs_set_glyph_v_advance_func(funcs, _bmp_get_glyph_v_advance, nullptr, nullptr);
		hb_font_funcs_set_glyph_v_origin_func(funcs, _bmp_get_glyph_v_origin, nullptr, nullptr);
		hb_font_funcs_set_glyph_h_kerning_func(funcs, _bmp_get_glyph_h_kerning, nullptr, nullptr);
		hb_font_funcs_set_glyph_extents_func(funcs, _bmp_get_glyph_extents, nullptr, nullptr);
		hb_font_funcs_make_immutable(funcs);
	}
}
void TextServerAdvanced::_bmp_free_font_funcs() {
	if (funcs != nullptr) {
		hb_font_funcs_destroy(funcs);
		funcs = nullptr;
	}
}
void TextServerAdvanced::_bmp_font_set_funcs(hb_font_t *p_font, TextServerAdvanced::FontForSizeAdvanced *p_face, bool p_unref) {
	hb_font_set_funcs(p_font, funcs, _bmp_font_create(p_face, p_unref), _bmp_font_destroy);
}
hb_font_t *TextServerAdvanced::_bmp_font_create(TextServerAdvanced::FontForSizeAdvanced *p_face, hb_destroy_func_t p_destroy) {
	hb_font_t *font;
	hb_face_t *face = hb_face_create(nullptr, 0);
	font = hb_font_create(face);
	hb_face_destroy(face);
	_bmp_font_set_funcs(font, p_face, false);
	return font;
}
_FORCE_INLINE_ bool is_ain(char32_t p_chr) {