### 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)
_THREAD_SAFE_METHOD_
	const ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, RID());
	MutexLock lock(sd->mutex);
	if (sd->parent != RID()) {
		return _shaped_text_substr(sd->parent, p_start, p_length);
	}
	if (!sd->valid) {
		const_cast<TextServerAdvanced *>(this)->_shaped_text_shape(p_shaped);
	}
	ERR_FAIL_COND_V(p_start < 0 || p_length < 0, RID());
	ERR_FAIL_COND_V(sd->start > p_start || sd->end < p_start, RID());
	ERR_FAIL_COND_V(sd->end < p_start + p_length, RID());
	ShapedTextDataAdvanced *new_sd = memnew(ShapedTextDataAdvanced);
	new_sd->parent = p_shaped;
	new_sd->start = p_start;
	new_sd->end = p_start + p_length;
	new_sd->orientation = sd->orientation;
	new_sd->direction = sd->direction;
	new_sd->custom_punct = sd->custom_punct;
	new_sd->para_direction = sd->para_direction;
	new_sd->base_para_direction = sd->base_para_direction;
	for (int i = 0; i < TextServer::SPACING_MAX; i++) {
		new_sd->extra_spacing[i] = sd->extra_spacing[i];