### 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)
ccpert("ccp_BD"));
		ccpert("ccp_IN"));
		ccp.digits = U"𑄶𑄷𑄸𑄹𑄺𑄻𑄼𑄽𑄾𑄿.";
		ccpsign = U"%";
		ccp.exp = U"e";
		num_systems.push_back(ccp);
	}
	// Adlam numerals.
	{
		NumSystemData ff;
		ffert("ff")); // Fulah
		ffert("ff_Adlm_BF"));
		ffert
		ffert("ff_Adlm_GH"));
		ffert("ff_Adlm_GM"));
		ffert("ff_Adlm_GN"));
		ffert("ff_Adlm_GW"));
		ffert("ff_Adlm_LR"));
		ffert("ff_Adlm_MR"));
		ffert("ff_Adlm_NE"));
		ffert("ff_Adlm_NG"));
		ffert("ff_Adlm_SL"));
		ffert("ff_Adlm_SN"));
		ff.digits = U"𞥐𞥑𞥒𞥓𞥔𞥕𞥖𞥗𞥘𞥙.";
		ffsign = U"%";
		ff.exp = U"e";
		num_systems.push_back(ff);
	}
}
String TextServerAdvanced::_format_number(const String &p_string, const String &p_language) const {