### 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)
return oversampling;
}
void TextServerAdvanced::_font_set_global_oversampling(double p_oversampling) {
	_THREAD_SAFE_METHOD_
	if (oversampling != p_oversampling) {
		oversampling = p_oversampling;
		List<RID> fonts;
		font_owner.get_owned_list(&fonts);
		bool font_cleared = false;
		for (const RID &E : fonts) {
			if (!_font_is_multichannel_signed_distance_field(E) && _font_get_oversampling(E) <= 0) {
				_font_clear_size_cache(E);
				font_cleared = true;
			}
		}
		if (font_cleared) {
			List<RID> text_bufs;
			shaped_owner.get_owned_list(&text_bufs);
			for (const RID &E : text_bufs) {
				invalidate(shaped_owner.get_or_null(E), false);
			}
		}
	}
}
int64_t TextServerAdvanced::_convert_pos(const String &p_utf32, const Char16String &p_utf16, int64_t p_pos) const {