### 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 (mh > texsize) { 
			texsize = next_power_of_2(mh);
		}
		ShelfPackTexture tex = ShelfPackTexture(texsize, texsize);
		tex.format = p_image_format;
		tex.imgdata.resize(texsize * texsize * p_color_size);
		{
			
			uint8_t *w = tex.imgdata.ptrw();
			ERR_FAIL_COND_V(texsize * texsize * p_color_size > tex.imgdata.size(), ret);
			
			
			if (p_color_size == 2) {
				for (int i = 0; i < texsize * texsize * p_color_size; i += 2) { 
					w[i + 0] = 255;
					w[i + 1] = 0;
				}
			} else if (p_color_size == 4) {
				for (int i = 0; i < texsize * texsize * p_color_size; i += 4) { 
					w[i + 0] = 255;
					w[i + 1] = 255;
					w[i + 2] = 255;
					w[i + 3] = 0;
				}
			} else {
				ERR_FAIL_V(ret);
			}
		}
		p_data->textures.push_back(tex);