### 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)
}
bool TextServerAdvanced::_spoof_check(const String &p_string) const {
#ifndef ICU_STATIC_DATA
	if (!icu_data_loaded) {
		return false;
	}
#endif
	UErrorCode status = U_ZERO_ERROR;
	Char16String utf16 = p_string.utf16();
	if (allowed == nullptr) {
		allowed = uset_openEmpty();
		uset_addAll(allowed, uspoof_getRecommendedSet(&status));
		uset_addAll(allowed, uspoof_getInclusionSet(&status));
	}
	if (sc_spoof == nullptr) {
		sc_spoof = uspoof_open(&status);
		uspoof_setAllowedChars(sc_spoof, allowed, &status);
		uspoof_setRestrictionLevel(sc_spoof, USPOOF_MODERATELY_RESTRICTIVE);
	}
	int32_t bitmask = uspoof_check(sc_spoof, utf16.get_data(), -1, NULL, &status);
	ERR_FAIL_COND_V_MSG(U_FAILURE(status), false, u_errorName(status));
	return (bitmask != 0);
}
String TextServerAdvanced::_strip_diacritics(const String &p_string) const {
#ifndef ICU_STATIC_DATA
	if (!icu_data_loaded) {
		return TextServer::strip_diacritics(p_string);
	}
#endif
	UErrorCode err = U_ZERO_ERROR;