### 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)
SEQ_STARTED,
		SEQ_STARTED_VIR,
		SEQ_NEAR_END,
	};
	const char32_t *str = p_string.ptr();
	int len = p_string.length();
	if (len 
		return false; // Empty string.
	}
	UErrorCode err = U_ZERO_ERROR;
	Char16String utf16 = p_string.utf16();
	const UNormalizer2 *norm_c = unorm2_getNFCInstance(&err);
	if (U_FAILURE(err)) {
		return fals load normalizer.
	}
	bool isnurom = unorm2_isNormalized(norm_c, utf16.get_data(), utf16.length(), &err);
	if (U_FAILURE(err) || !isnurom) {
		return false; // Do not conform to Normalization Form C.
	}
	UAX31SequenceStatus A1_sequence__STARTED;
	UScriptCode A1_scr = USCRIPT_INHERITED;
	UAX31SequenceStatus nce__STARTED;
	UScriptCode A2_scr = USCRIPT_INHERITED;
	UAX31SequenceStatus e__STARTED;
	UScriptCode B_scr = USCRIPT_INHERITED;
	for (int i = 0; i < len; i++) {
		err = U_ZERO_ERROR;
		UScriptCode scr = uscript_getScript(str[i], &err);
		if (U_FAILURE(err)) {
			return false; // Invalid script.