### 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 (U_FAILURE(err)) {
							ubidi_close(bidi_iter);
							bidi_iter = nullptr;
							ERR_PRINT(vformat("BiDi reordering for the line failed: %s", u_errorName(err)));
						}
					}
				} else {
					bidi_iter = nullptr;
					ERR_PRINT(vformat("BiDi iterator allocation for the line failed: %s", u_errorName(err)));
				}
			}
			p_new_sd->bidi_iter.push_back(bidi_iter);
			err = U_ZERO_ERROR;
			int bidi_run_count = 1;
			if (bidi_iter) {
				bidi_run_count = ubidi_countRuns(bidi_iter, &err);
				if (U_FAILURE(err)) {
					ERR_PRINT(u_errorName(err));
				}
			}
			for (int i = 0; i < bidi_run_count; i++) {
				int32_t _bidi_run_start = 0;
				int32_t _bidi_run_length = end - start;
				if (bidi_iter) {
					ubidi_getVisualRun(bidi_iter, i, &_bidi_run_start, &_bidi_run_length);
				}
				int32_t bidi_run_start = _convert_pos(p_sd, ov_start + start + _bidi_run_start);
				int32_t bidi_run_end = _convert_pos(p_sd, ov_start + start + _bidi_run_start + _bidi_run_length);
				for (int j = 0; j < sd_size; j++) {