### 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)
#include <godot_cpp/classes/rendering_server.hpp>
#include <godot_cpp/classes/translation_server.hpp>
#include <godot_cpp/core/error_macros.hpp>
using namespace godot;
#define GLOBAL_GET(m_var) ProjectSettings::get_singleton()->get_setting_with_override(m_var)
#else
#include "core/config/project_settings.h"
#include "core/error/error_macros.h"
#include "core/object/worker_thread_pool.h"
#include "core/string/print_string.h"
#include "core/string/translation.h"
#include "scene/resources/image_texture.h"
#include "modules/modules_enabled.gen.h" 
#endif
#ifdef ICU_STATIC_DATA
#include "icudata.gen.h"
#endif
#ifdef MODULE_MSDFGEN_ENABLED
#include <core/ShapeDistanceFinder.h>
#include <core/contour-combiners.h>
#include <core/edge-selectors.h>
#include <msdfgen.h>
#endif
#ifdef MODULE_SVG_ENABLED
#ifdef MODULE_FREETYPE_ENABLED
#include "thorvg_svg_in_ot.h"
#endif
#endif
hb_font_funcs_t *TextServerAdvanced::funcs = nullptr;
TextServerAdvanced::bmp_font_t *TextServerAdvanced::_bmp_font_create(TextServerAdvanced::FontForSizeAdvanced *p_face, bool p_unref) {