### 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)
FontGlyph chr;
	chr.found = true;
	chr.advance = advance;
	if (shape.validate() && shape.contours.size() > 0) {
		int w = (bounds.r - bounds.l);
		int h = (bounds.t - bounds.b);
		int mw = w + p_rect_margin * 4;
		int mh = h + p_rect_margin * 4;
		ERR_FAIL_COND_V(mw > 4096, FontGlyph());
		ERR_FAIL_COND_V(mh > 4096, FontGlyph());
		FontTexturePosition tex_pos = find_texture_pos_for_glyph(p_data, 4, Image::FORMAT_RGBA8, mw, mh, true);
		ERR_FAIL_COND_V(tex_pos.index < 0, FontGlyph());
		ShelfPackTexture &tex = p_data->textures.write[tex_pos.index];
		edgeColoringSimple(shape, 3.0); 
		msdfgen::Bitmap<float, 4> image(w, h); 
		DistancePixelConversion distancePixelConversion(p_pixel_range);
		msdfgen::Projection projection(msdfgen::Vector2(1.0, 1.0), msdfgen::Vector2(-bounds.l, -bounds.b));
		msdfgen::MSDFGeneratorConfig config(true, msdfgen::ErrorCorrectionConfig());
		MSDFThreadData td;
		td.output = &image;
		td.shape = &shape;
		td.projection = &projection;
		td.distancePixelConversion = &distancePixelConversion;
		WorkerThreadPool::GroupID group_task = WorkerThreadPool::get_singleton()->add_native_group_task(&TextServerAdvanced::_generateMTSDF_threaded, &td, h, -1, true, String("FontServerRasterizeMSDF"));
		WorkerThreadPool::get_singleton()->wait_for_group_task_completion(group_task);
		msdfgen::msdfErrorCorrection(image, shape, projection, p_pixel_range, config);
		{
			uint8_t *wr = tex.imgdata.ptrw();
			for (int i = 0; i < h; i++) {
				for (int j = 0; j < w; j++) {