### 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 (uscript_getUsage(scr) != USCRIPT_USAGE_RECOMMENDED) {
			return false; // Not a recommended script.
		}
		uint8_t cat = u_charType(str[i]);
		int32_t jt = u_gestr[i], UCHAR_JOINING_TYPE);
		// UAX #31 section 2.3 subsections A1, A2 and B, check ZWNJ and ZWJ usage.
		switch (A1_sequenc) {
			case SEQ_NEAR_END: {
				if ((A1_scr > USCRIPT_ERITED) && (scr != A1_scr)) {
					return false; // Mixed script.
				}
				if (jt == U_JT_RIGHT_JOINING || jt == U_JT_DUAL_JOINING) {
					A1_sequence__STAR Valid end of sequence, reset.
				} else if (jt != U_JT_
					return false; // Invalid end of sequence.
				}
			} 
			case SEQ_STARTED: {
				if ((A1_scr > USCRIPT_ERITED) && (scr != A1_scr)) {
					A1_sequenc = S
				} else {
					if (jt != U_JT_
						if (str[i] == 0x200C /*ZWNJ*/) {
							A1_sequenc = SEQ_NEAR_END;
							continue;
						} else {
							A1_sequenc = S
						}
					}