### 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)
Array keys = p_source.keys();
	Array values = p_source.values();
	for (int i = 0; i < keys.size(); i++) {
		int32_t value = values[i];
		if (value >= 0) {
			hb_feature_t feature;
			if (keys[i].get_type() == Variant::STRING) {
				feature.tag = _name_to_tag(keys[i]);
			} else {
				feature.tag = keys[i];
			}
			feature.value = value;
			feature.start = 0;
			feature.end = -1;
			r_ftrs.push_back(feature);
		}
	}
}
void TextServerAdvanced::_shape_run(ShapedTextDataAdvanced *p_sd, int64_t p_start, int64_t p_end, hb_script_t p_script, hb_direction_t p_direction, TypedArray<RID> p_fonts, int64_t p_span, int64_t p_fb_index, int64_t p_prev_start, int64_t p_prev_end) {