### 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)
FontTexturePosition ret;
	int mw = p_width;
	int mh = p_height;
	ShelfPackTexture *ct = p_data->textures.ptrw();
	for (int32_t i = 0; i < p_data->textures.size(); i++) {
		if (p_image_format != ct[i].format) {
			continue;
		}
		if (mw > ct[i].texture_w || mh > ct[i].texture_h) { 
			continue;
		}
		ret = ct[i].pack_rect(i, mh, mw);
		if (ret.index != -1) {
			
		}
	}
	if (ret.index == -1) {
		
		int texsize = MAX(p_data->size.x * p_data->oversampling * 8, 256);
		texsize = next_power_of_2(texsize);
		if (p_msdf) {
			texsize = MIN(texsize, 2048);
		} else {
			texsize = MIN(texsize, 1024);
		}
		if (mw > texsize) { 
			texsize = next_power_of_2(mw);