### 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)
int end = MIN(_convert_pos_inv(p_sd, p_start + p_length), _convert_pos_inv(p_sd, p_sd->bidi_override[ov].y)) - ov_start;
			ERR_FAIL_COND_V_MSG((start < 0 || end - start > p_new_sd->utf16.length()), false, "Invalid BiDi override range.");
			
			UBiDi *bidi_iter = nullptr;
			if (p_sd->bidi_iter[ov]) {
				bidi_iter = ubidi_openSized(end - start, 0, &err);
				if (U_SUCCESS(err)) {
					ubidi_setLine(p_sd->bidi_iter[ov], start, end, bidi_iter, &err);
					if (U_FAILURE(err)) {
						
						err = U_ZERO_ERROR;
						const UChar *data = p_sd->utf16.get_data();
						switch (static_cast<TextServer::Direction>(p_sd->bidi_override[ov].z)) {
							case DIRECTION_LTR: {
								ubidi_setPara(bidi_iter, data + start, end - start, UBIDI_LTR, nullptr, &err);
							} 
							case DIRECTION_RTL: {
								ubidi_setPara(bidi_iter, data + start, end - start, UBIDI_RTL, nullptr, &err);
							} 
							case DIRECTION_INHERITED: {
								ubidi_setPara(bidi_iter, data + start, end - start, p_sd->base_para_direction, nullptr, &err);
							} 
							case DIRECTION_AUTO: {
								UBiDiDirection direction = ubidi_getBaseDirection(data + start, end - start);
								if (direction != UBIDI_NEUTRAL) {
									ubidi_setPara(bidi_iter, data + start, end - start, direction, nullptr, &err);
								} else {
									ubidi_setPara(bidi_iter, data + start, end - start, p_sd->base_para_direction, nullptr, &err);
								}
							}