### 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(!fd);
	MutexLock lock(fd->mutex);
	Vector2i size = _get_size(fd, p_size);
	ERR_FAIL_COND(!_ensure_cache_for_size(fd, size));
	int32_t index = p_index & 0xffffff; 
	bool lcd_aa = false;
#ifdef MODULE_FREETYPE_ENABLED
	if (!fd->msdf && fd->cache[size]->face) {
		
		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) {
				lcd_aa = true;
				index = index | (layout << 24);
			}
		}
		
		if ((fd->subpixel_positioning == SUBPIXEL_POSITIONING_ONE_QUARTER) || (fd->subpixel_positioning == SUBPIXEL_POSITIONING_AUTO && size.x <= SUBPIXEL_POSITIONING_ONE_QUARTER_MAX_SIZE)) {
			int xshift = (int)(Math::floor(4 * (p_pos.x + 0.125)) - 4 * Math::floor(p_pos.x + 0.125));
			index = index | (xshift << 27);
		} else if ((fd->subpixel_positioning == SUBPIXEL_POSITIONING_ONE_HALF) || (fd->subpixel_positioning == SUBPIXEL_POSITIONING_AUTO && size.x <= SUBPIXEL_POSITIONING_ONE_HALF_MAX_SIZE)) {
			int xshift = (int)(Math::floor(2 * (p_pos.x + 0.25)) - 2 * Math::floor(p_pos.x + 0.25));
			index = index | (xshift << 27);
		}