### 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)
bmp_font_t *bm_font = memnew(bmp_font_t);
	if (!bm_font) {
		return nullptr;
	}
	bm_font->face = p_face;
	bm_font->unref = p_unref;
	return bm_font;
}
void TextServerAdvanced::_bmp_font_destroy(void *p_data) {
	bmp_font_t *bm_font = static_cast<bmp_font_t *>(p_data);
	memdelete(bm_font);
}
hb_bool_t TextServerAdvanced::_bmp_get_nominal_glyph(hb_font_t *p_font, void *p_font_data, hb_codepoint_t p_unicode, hb_codepoint_t *r_glyph, void *p_user_data) {
	const bmp_font_t *bm_font = static_cast<const bmp_font_t *>(p_font_data);
	if (!bm_font->face) {
		return false;
	}
	if (!bm_font->face->glyph_map.has(p_unicode)) {
		if (bm_font->face->glyph_map.has(0xf000u + p_unicode)) {
			*r_glyph = 0xf000u + p_unicode;
			return true;
		} else {
			return false;
		}
	}
	*r_glyph = p_unicode;
	return true;
}
hb_position_t TextServerAdvanced::_bmp_get_glyph_h_advance(hb_font_t *p_font, void *p_font_data, hb_codepoint_t p_glyph, void *p_user_data) {