### 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)
wr[ofs + 0] = bitmap.buffer[ofs_color + bitmap.pitch * 2];
							wr[ofs + 1] = bitmap.buffer[ofs_color + bitmap.pitch];
							wr[ofs + 2] = bitmap.buffer[ofs_color + 0];
							wr[ofs + 3] = 255;
						} else {
							wr[ofs + 0] = bitmap.buffer[ofs_color + 0];
							wr[ofs + 1] = bitmap.buffer[ofs_color + bitmap.pitch];
							wr[ofs + 2] = bitmap.buffer[ofs_color + bitmap.pitch * 2];
							wr[ofs + 3] = 255;
						}
					} 
					default:
						ERR_FAIL_V_MSG(FontGlyph(), "Font uses unsupported pixel format: " + String::num_int64(bitmap.pixel_mode) + ".");
						
				}
			}
		}
	}
	tex.dirty = true;
	FontGlyph chr;
	chr.advance = advance * p_data->scale / p_data->oversampling;
	chr.texture_idx = tex_pos.index;
	chr.found = true;
	chr.uv_rect = Rect2(tex_pos.x + p_rect_margin, tex_pos.y + p_rect_margin, w + p_rect_margin * 2, h + p_rect_margin * 2);
	chr.rect.position = Vector2(xofs - p_rect_margin, -yofs - p_rect_margin) * p_data->scale / p_data->oversampling;
	chr.rect.size = chr.uv_rect.size * p_data->scale / p_data->oversampling;
	return chr;
}
#endif
_FORCE_INLINE_ bool TextServerAdvanced::_ensure_glyph(FontAdvanced *p_font_data, const Vector2i &p_size, int32_t p_glyph) const {