### 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)
_insert_feature("character_variant_50", HB_TAG('c', 'v', '5', '0'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_51", HB_TAG('c', 'v', '5', '1'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_52", HB_TAG('c', 'v', '5', '2'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_53", HB_TAG('c', 'v', '5', '3'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_54", HB_TAG('c', 'v', '5', '4'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_55", HB_TAG('c', 'v', '5', '5'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_56", HB_TAG('c', 'v', '5', '6'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_57", HB_TAG('c', 'v', '5', '7'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_58", HB_TAG('c', 'v', '5', '8'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_59", HB_TAG('c', 'v', '5', '9'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_60", HB_TAG('c', 'v', '6', '0'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_61", HB_TAG('c', 'v', '6', '1'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_62", HB_TAG('c', 'v', '6', '2'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_63", HB_TAG('c', 'v', '6', '3'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_64", HB_TAG('c', 'v', '6', '4'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_65", HB_TAG('c', 'v', '6', '5'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_66", HB_TAG('c', 'v', '6', '6'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_67", HB_TAG('c', 'v', '6', '7'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_68", HB_TAG('c', 'v', '6', '8'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_69", HB_TAG('c', 'v', '6', '9'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_70", HB_TAG('c', 'v', '7', '0'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_71", HB_TAG('c', 'v', '7', '1'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_72", HB_TAG('c', 'v', '7', '2'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_73", HB_TAG('c', 'v', '7', '3'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_74", HB_TAG('c', 'v', '7', '4'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_75", HB_TAG('c', 'v', '7', '5'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_76", HB_TAG('c', 'v', '7', '6'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_77", HB_TAG('c', 'v', '7', '7'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_78", HB_TAG('c', 'v', '7', '8'), Variant::Type::BOOL, false);
	_insert_feature("character_variant_79", HB_TAG('c', 'v', '7', '9'), Variant::Type::BOOL, false);