### 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)
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) {
	return u_gep_chr, UCHAR_JOINING_GROUP) == U_JG_AIN;
}
_FORCE_INLINE_ bool is_alef(char32_t p_chr) {