### 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)

p_font_data->supported_scripts.insert(HB_SCRIPT_KAYAH_LI);
				}
				if (os2->ulUnicodeRange4 & 1L << 21) {
					p_font_data->supported_scripts.insert(HB_SCRIPT_REJANG);
				}
				if (os2->ulUnicodeRange4 & 1L << 22) {
					p_font_data->supported_scripts.insert(HB_SCRIPT_CHAM);
				}
				if (os2->ulUnicodeRange4 & 1L << 25) {
					p_font_data->supported_scripts.insert(HB_SCRIPT_ANATOLIAN_HIEROGLYPHS);
				}
			}
			
			p_font_data->supported_features.clear();
			count = hb_ot_layout_table_get_feature_tags(hb_face, HB_OT_TAG_GSUB, 0, nullptr, nullptr);
			if (count != 0) {
				hb_tag_t *feature_tags = (hb_tag_t *)memalloc(count * sizeof(hb_tag_t));
				hb_ot_layout_table_get_feature_tags(hb_face, HB_OT_TAG_GSUB, 0, &count, feature_tags);
				for (unsigned int i = 0; i < count; i++) {
					Dictionary ftr;
#if HB_VERSION_ATLEAST(2, 1, 0)
					hb_ot_name_id_t lbl_id;
					if (hb_ot_layout_feature_get_name_ids(hb_face, HB_OT_TAG_GSUB, i, &lbl_id, nullptr, nullptr, nullptr, nullptr)) {
						PackedInt32Array lbl;
						unsigned int text_size = hb_ot_name_get_utf32(hb_face, lbl_id, hb_language_from_string(TranslationServer::get_singleton()->get_tool_locale().ascii().get_data(), -1), nullptr, nullptr) + 1;
						lbl.resize(text_size);
						memset((uint32_t *)lbl.ptrw(), 0, sizeof(uint32_t) * text_size);
						hb_ot_name_get_utf32(hb_face, lbl_id, hb_language_from_string(TranslationServer::get_singleton()->get_tool_locale().ascii().get_data(), -1), &text_size, (uint32_t *)lbl.ptrw());
						ftr["label"] = String((const char32_t *)lbl.ptr());
					}