### 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)
const ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, TextServer::ORIENTATION_HORIZONTAL);
	MutexLock lock(sd->mutex);
	return sd->orientation;
}
int64_t TextServerAdvanced::_shaped_get_span_count(const RID &p_shaped) const {
	ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, 0);
	return sd->spans.size();
}
Variant TextServerAdvanced::_shaped_get_span_meta(const RID &p_shaped, int64_t p_index) const {
	ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, Variant());
	ERR_FAIL_INDEX_V(p_index, sd->spans.size(), Variant());
	return sd->spans[p_index].meta;
}
void TextServerAdvanced::_shaped_set_span_update_font(const RID &p_shaped, int64_t p_index, const TypedArray<RID> &p_fonts, int64_t p_size, const Dictionary &p_opentype_features) {
	ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND(!sd);
	ERR_FAIL_INDEX(p_index, sd->spans.size());
	ShapedTextDataAdvanced::Span &span = sd->spans.ptrw()[p_index];
	span.fonts = p_fonts;
	span.font_size = p_size;
	span.features = p_opentype_features;
	invalidate(sd, false);
}
bool TextServerAdvanced::_shaped_text_add_string(const RID &p_shaped, const String &p_text, const TypedArray<RID> &p_fonts, int64_t p_size, const Dictionary &p_opentype_features, const String &p_language, const Variant &p_meta) {