### 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)
hb_language_t lang = hb_language_from_string(p_sd->spans[p_span].language.ascii().get_data(), -1);
		hb_buffer_set_language(p_sd->hb_buffer, lang);
	}
	hb_buffer_add_utf32(p_sd->hb_buffer, (const uint32_t *)p_sd->text.ptr(), p_sd->text.length(), p_start, p_end - p_start);
	Vector<hb_feature_t> ftrs;
	_add_featuers(_font_get_opentype_feature_overrides(f), ftrs);
	_add_featuers(p_sd->spans[p_span].features, ftrs);
	hb_shape(hb_font, p_sd->hb_buffer, ftrs.is_empty() ? nullptr : &ftrs[0], ftrs.size());
	unsigned int glyph_count = 0;
	hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos(p_sd->hb_buffer, &glyph_count);
	hb_glyph_position_t *glyph_pos = hb_buffer_get_glyph_positions(p_sd->hb_buffer, &glyph_count);
	int mod = 0;
	if (fd->antialiasing == FONT_ANTIALIASING_LCD) {
		TextServer::FontLCDSubpixelLayout layout = (TextServer::FontLCDSubpixelLayout)(int)GLOBAL_GET("gui/theme/lcd_subpixel_layout");
		if (layout != FONT_LCD_SUBPIXEL_LAYOUT_NONE) {
			mod = (layout << 24);
		}
	}
	
	if (glyph_count > 0) {
		Glyph *w = (Glyph *)memalloc(glyph_count * sizeof(Glyph));
		int end = (p_direction == HB_DIRECTION_RTL || p_direction == HB_DIRECTION_BTT) ? p_end : 0;
		uint32_t last_cluster_id = UINT32_MAX;
		unsigned int last_cluster_index = 0;
		bool last_cluster_valid = true;
		for (unsigned int i = 0; i < glyph_count; i++) {
			if ((i > 0) && (last_cluster_id != glyph_info[i].cluster)) {
				if (p_direction == HB_DIRECTION_RTL || p_direction == HB_DIRECTION_BTT) {
					end = w[last_cluster_index].start;
				} else {