### 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)
fd->underline_thickness = (FT_MulFix(fd->face->underline_thickness, fd->face->size->metrics.y_scale) / 64.0) / fd->oversampling * fd->scale;
#if HB_VERSION_ATLEAST(3, 3, 0)
		hb_font_set_synthetic_slant(fd->hb_handle, p_font_data->transform[0][1]);
#else
#ifndef _MSC_VER
#warning Building with HarfBuzz < 3.3.0, synthetic slant offset correction disabled.
#endif
#endif
		if (!p_font_data->face_init) {
			
			if (fd->face->family_name != nullptr) {
				p_font_data->font_name = String::utf8((const char *)fd->face->family_name);
			}
			if (fd->face->style_name != nullptr) {
				p_font_data->style_name = String::utf8((const char *)fd->face->style_name);
			}
			p_font_data->weight = _font_get_weight_by_name(p_font_data->style_name.to_lower());
			p_font_data->stretch = _font_get_stretch_by_name(p_font_data->style_name.to_lower());
			p_font_data->style_flags = 0;
			if ((fd->face->style_flags & FT_STYLE_FLAG_BOLD) || p_font_data->weight >= 700) {
				p_font_data->style_flags.set_flag(FONT_BOLD);
			}
			if ((fd->face->style_flags & FT_STYLE_FLAG_ITALIC) || _is_ital_style(p_font_data->style_name.to_lower())) {
				p_font_data->style_flags.set_flag(FONT_ITALIC);
			}
			if (fd->face->face_flags & FT_FACE_FLAG_FIXED_WIDTH) {
				p_font_data->style_flags.set_flag(FONT_FIXED_WIDTH);
			}
			hb_face_t *hb_face = hb_font_get_face(fd->hb_handle);