### 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)
if (fd->msdf) {
					Point2 cpos = p_pos;
					cpos += gl.rect.position * (double)p_size / (double)fd->msdf_source_size;
					Size2 csize = gl.rect.size * (double)p_size / (double)fd->msdf_source_size;
					RenderingServer::get_singleton()->canvas_item_add_msdf_texture_rect_region(p_canvas, Rect2(cpos, csize), texture, gl.uv_rect, modulate, p_outline_size, fd->msdf_range, (double)p_size / (double)fd->msdf_source_size);
				} else {
					Point2 cpos = p_pos;
					double scale = _font_get_scale(p_font_rid, p_size);
					if ((fd->subpixel_positioning == SUBPIXEL_POSITIONING_ONE_QUARTER) || (fd->subpixel_positioning == SUBPIXEL_POSITIONING_AUTO && size.x <= SUBPIXEL_POSITIONING_ONE_QUARTER_MAX_SIZE)) {
						cpos.x = cpos.x + 0.125;
					} else if ((fd->subpixel_positioning == SUBPIXEL_POSITIONING_ONE_HALF) || (fd->subpixel_positioning == SUBPIXEL_POSITIONING_AUTO && size.x <= SUBPIXEL_POSITIONING_ONE_HALF_MAX_SIZE)) {
						cpos.x = cpos.x + 0.25;
					}
					if (scale == 1.0) {
						cpos.y = Math::floor(cpos.y);
						cpos.x = Math::floor(cpos.x);
					}
					cpos += gl.rect.position;
					Size2 csize = gl.rect.size;
					if (lcd_aa) {
						RenderingServer::get_singleton()->canvas_item_add_lcd_texture_rect_region(p_canvas, Rect2(cpos, csize), texture, gl.uv_rect, modulate);
					} else {
						RenderingServer::get_singleton()->canvas_item_add_texture_rect_region(p_canvas, Rect2(cpos, csize), texture, gl.uv_rect, modulate, false, false);
					}
				}
			}
		}
	}
}
bool TextServerAdvanced::_font_is_language_supported(const RID &p_font_rid, const String &p_language) const {