### 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)
ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND(!sd);
	MutexLock lock(sd->mutex);
	sd->parent = RID();
	sd->start = 0;
	sd->end = 0;
	sd->text = String();
	sd->spans.clear();
	sd->objects.clear();
	sd->bidi_override.clear();
	invalidate(sd, true);
}
void TextServerAdvanced::_shaped_text_set_direction(const RID &p_shaped, TextServer::Direction p_direction) {
	ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_MSG(p_direction == DIRECTION_INHERITED, "Invalid text direction.");
	ERR_FAIL_COND(!sd);
	MutexLock lock(sd->mutex);
	if (sd->direction != p_direction) {
		if (sd->parent != RID()) {
			full_copy(sd);
		}
		sd->direction = p_direction;
		invalidate(sd, false);
	}
}
TextServer::Direction TextServerAdvanced::_shaped_text_get_direction(const RID &p_shaped) const {