### Godot version

v4.2.dev4.official [549fcce5f]

### System information

Ubuntu 20.04 LTS

### Issue description

See title.

### Steps to reproduce

1. Create a new project
2. Create a csv file that includes the following
```
key,ar
key,placeholder
```
3. Add the generated `.translation` file to Project -> Project Settings... -> Localization
4. In Project -> Project Settings... -> Internationalization -> Locale, set `Test` to `ar`
5. Add a `LineEdit` node and type `-=[]{}`
6. Run the project, and notice that the text is on the right side, but the symbols are incorrectly in LTR (`-=[]{}`).  Correct output is `{}[]=-`
7. Back in the editor, add a single Arabic letter (any will do), and notice that `LineEdit` immediately (and correctly) flips the symbols, and the newly-added Arabic letter, to RTL.

**Notes**
- Identical behavior is seen with `TextEdit`.
- The purpose of steps 2-4 are to simulate an Arabic environment when the project is run, despite `OS.get_locale() == "en"` (or your system's current language).

### Minimal reproduction project

[rtlsymbols.zip](https://github.com/godotengine/godot/files/12525509/rtlsymbols.zip)
memdelete(fd);
		ERR_FAIL_V_MSG(false, "FreeType: Can't load dynamic font, engine is compiled without FreeType support!");
#endif
	} else {
		
		fd->hb_handle = _bmp_font_create(fd, nullptr);
	}
	p_font_data->cache[p_size] = fd;
	return true;
}
_FORCE_INLINE_ void TextServerAdvanced::_font_clear_cache(FontAdvanced *p_font_data) {
	MutexLock ftlock(ft_mutex);
	for (const KeyValue<Vector2i, FontForSizeAdvanced *> &E : p_font_data->cache) {
		memdelete(E.value);
	}
	p_font_data->cache.clear();
	p_font_data->face_init = false;
	p_font_data->supported_features.clear();
	p_font_data->supported_varaitions.clear();
	p_font_data->supported_scripts.clear();
}
hb_font_t *TextServerAdvanced::_font_get_hb_handle(const RID &p_font_rid, int64_t p_size) const {
	FontAdvanced *fd = font_owner.get_or_null(p_font_rid);
	ERR_FAIL_COND_V(!fd, nullptr);
	MutexLock lock(fd->mutex);
	Vector2i size = _get_size(fd, p_size);
	ERR_FAIL_COND_V(!_ensure_cache_for_size(fd, size), nullptr);
	return fd->cache[size]->hb_handle;
}
RID TextServerAdvanced::_create_font() {