### 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)
start = 0;
		end = sd->glyphs.size();
		delta = +1;
	} else {
		start = sd->glyphs.size() - 1;
		end = -1;
		delta = -1;
	}
	Glyph *gl = sd->glyphs.ptrw();
	for (int i = start; i != end; i += delta) {
		if ((gl[i].flags & GRAPHEME_IS_TAB) == GRAPHEME_IS_TAB) {
			double tab_off = 0.0;
			while (tab_off <= off) {
				tab_off += p_tab_stops[tab_index];
				tab_index++;
				if (tab_index >= p_tab_stops.size()) {
					tab_index = 0;
				}
			}
			double old_adv = gl[i].advance;
			gl[i].advance = tab_off - off;
			sd->width += gl[i].advance - old_adv;
			off = 0;
			continue;
		}
		off += gl[i].advance * gl[i].repeat;
	}
	return 0.0;
}
void TextServerAdvanced::_shaped_text_overrun_trim_to_width(const RID &p_shaped_line, double p_width, BitField<TextServer::TextOverrunFlag> p_trim_flags) {