### 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 (sd->para_direction == DIRECTION_LTR) {
					start_pos = i;
					
				} else {
					end_pos = i;
					
				}
			}
		}
	}
	double justification_width;
	if (p_jst_flags.has_flag(JUSTIFICATION_CONSTRAIN_ELLIPSIS)) {
		if (sd->overrun_trim_data.trim_pos >= 0) {
			if (sd->para_direction == DIRECTION_RTL) {
				start_pos = sd->overrun_trim_data.trim_pos;
			} else {
				end_pos = sd->overrun_trim_data.trim_pos;
			}
			justification_width = sd->width_trimmed;
		} else {
			return Math::ceil(sd->width);
		}
	} else {
		justification_width = sd->width;
	}
	if (p_jst_flags.has_flag(JUSTIFICATION_TRIM_EDGE_SPACES)) {
		
		while ((start_pos < end_pos) && ((sd->glyphs[start_pos].flags & GRAPHEME_IS_SPACE) == GRAPHEME_IS_SPACE || (sd->glyphs[start_pos].flags & GRAPHEME_IS_BREAK_HARD) == GRAPHEME_IS_BREAK_HARD || (sd->glyphs[start_pos].flags & GRAPHEME_IS_BREAK_SOFT) == GRAPHEME_IS_BREAK_SOFT)) {
			justification_width -= sd->glyphs[start_pos].advance * sd->glyphs[start_pos].repeat;
			sd->glyphs.write[start_pos].advance = 0;