### 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)
Vector<ShapedTextDataAdvanced::Span> &spans = sd->spans;
	if (sd->parent != RID()) {
		ShapedTextDataAdvanced *parent_sd = shaped_owner.get_or_null(sd->parent);
		ERR_FAIL_COND(!parent_sd->valid);
		spans = parent_sd->spans;
	}
	if (spans.size(
		return;
	}
	int sd_size = sd->glyphs.size();
	int last_gl_font_size = sd_glyphs[sd_size - 1].font_size;
	
	RID dot_gl_font_rid = sd_glyphs[sd_size - 1].font_rid;
	if (!_font_has_char(dot_gl_font_rid, '.')) {
		const Array &fonts = spans[spans.size() - 1].fonts;
		for (int i = 0; i < fonts.size(); i++) {
			if (_font_has_char(fonts[i], '.')) {
				dot_gl_font_rid = fonts[i];
				
			}
		}
	}
	RID whitespace_gl_font_rid = sd_glyphs[sd_size - 1].font_rid;
	if (!_font_has_char(whitespace_gl_font_rid, '.')) {
		const Array &fonts = spans[spans.size() - 1].fonts;
		for (int i = 0; i < fonts.size(); i++) {
			if (_font_has_char(fonts[i], ' ')) {
				whitespace_gl_font_rid = fonts[i];
				
			}