### 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 (prev != pos) {
						p_sd->chars.push_back(pos);
					}
					prev = pos;
				}
				ubrk_close(bi);
			} else {
				for (int j = r_start; j < r_end; j++) {
					if (prev != j) {
						p_sd->chars.push_back(j + 1 + p_sd->start);
					}
					prev = j;
				}
			}
			i++;
		}
		p_sd->chars_valid = true;
	}
}
PackedInt32Array TextServerAdvanced::_shaped_text_get_character_breaks(const RID &p_shaped) const {
	ShapedTextDataAdvanced *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, PackedInt32Array());
	MutexLock lock(sd->mutex);
	if (!sd->valid) {
		const_cast<TextServerAdvanced *>(this)->_shaped_text_shape(p_shaped);
	}
	_update_chars(sd);
	return sd->chars;
}
bool TextServerAdvanced::_shaped_text_update_breaks(const RID &p_shaped) {