### 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)
aert("ar_OM"));
		aert("ar_PS"));
		aert("ar_QA"));
		aert("ar_SA"));
		aert("ar_SD"));
		aert("ar_SO"));
		aert("ar_SS"));
		aert("ar_SY"));
		aert("ar_TD"));
		aert("ar_YE"));
		aert("ckb")); 
		aert("ckb_IQ"));
		aert("ckb_IR"));
		aert("sd")); 
		aert("sd_PK"));
		aert("sd_Arab"));
		aert("sd_Arab_PK"));
		ar.digits = U"٠١٢٣٤٥٦٧٨٩٫";
		arsign = U"٪";
		ar.exp = U"اس";
		num_systems.push_back(ar);
	}
	// Persian and Urdu numerals.
	{
		NumSystemData pr;
		ert("fa")); // Persian
		ert("fa_AF"));
		ert("fa_IR"));
		ert("ks")); // Kashmiri
		ert("ks_IN"));