### 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)
FontAdvanced *fd = font_owner.get_or_null(p_font_rid);
	ERR_FAIL_COND_V(!fd, Vector2());
	MutexLock lock(fd->mutex);
	Vector2i size = _get_size(fd, p_size);
	ERR_FAIL_COND_V(!_ensure_cache_for_size(fd, size), Vector2());
	int mod = 0;
	if (fd->antialiasing == FONT_ANTIALIASING_LCD) {
		TextServer::FontLCDSubpixelLayout layout = (TextServer::FontLCDSubpixelLayout)(int)GLOBAL_GET("gui/theme/lcd_subpixel_layout");
		if (layout != FONT_LCD_SUBPIXEL_LAYOUT_NONE) {
			mod = (layout << 24);
		}
	}
	if (!_ensure_glyph(fd, size, p_glyph | mod)) {
		return Vector2(); 
	}
	const HashMap<int32_t, FontGlyph> &gl = fd->cache[size]->glyph_map;
	Vector2 ea;
	if (fd->embolden != 0.0) {
		ea.x = fd->embolden * double(size.x) / 64.0;
	}
	double scale = _font_get_scale(p_font_rid, p_size);
	if (fd->msdf) {
		return (gl[p_glyph | mod].advance + ea) * (double)p_size / (double)fd->msdf_source_size;
	} else if ((scale == 1.0) && ((fd->subpixel_positioning == SUBPIXEL_POSITIONING_DISABLED) || (fd->subpixel_positioning == SUBPIXEL_POSITIONING_AUTO && size.x > SUBPIXEL_POSITIONING_ONE_HALF_MAX_SIZE))) {
		return (gl[p_glyph | mod].advance + ea).round();
	} else {
		return gl[p_glyph | mod].advance + ea;
	}
}
void TextServerAdvanced::_font_set_glyph_advance(const RID &p_font_rid, int64_t p_size, int64_t p_glyph, const Vector2 &p_advance) {