### 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 bmp_font_t *bm_font = static_cast<const bmp_font_t *>(p_font_data);
	if (!bm_font->face) {
		return false;
	}
	r_metrics->ascender = bm_font->face->ascent;
	r_metrics->descender = bm_font->face->descent;
	r_metrics->line_gap = 0;
	return true;
}
void TextServerAdvanced::_bmp_create_font_funcs() {
	if (funcs == nullptr) {
		funcs = hb_font_funcs_create();
		hb_font_funcs_set_font_h_extents_func(funcs, _bmp_get_font_h_extents, nullptr, nullptr);
		hb_font_funcs_set_nominal_glyph_func(funcs, _bmp_get_nominal_glyph, nullptr, nullptr);
		hb_font_funcs_set_glyph_h_advance_func(funcs, _bmp_get_glyph_h_advance, nullptr, nullptr);
		hb_font_funcs_set_glyph_v_advance_func(funcs, _bmp_get_glyph_v_advance, nullptr, nullptr);
		hb_font_funcs_set_glyph_v_origin_func(funcs, _bmp_get_glyph_v_origin, nullptr, nullptr);
		hb_font_funcs_set_glyph_h_kerning_func(funcs, _bmp_get_glyph_h_kerning, nullptr, nullptr);
		hb_font_funcs_set_glyph_extents_func(funcs, _bmp_get_glyph_extents, nullptr, nullptr);
		hb_font_funcs_make_immutable(funcs);
	}
}
void TextServerAdvanced::_bmp_free_font_funcs() {