Ignore name records with an unknown encoding

macOS Helvetica.ttc has such a name record:
```
platformID: 1 (mac)
platEncID: 4 (Arabic)
```
(see [encoding](https://learn.microsoft.com/en-us/typography/opentype/spec/name#macintosh-platform-platform-id--1))

fontTools has not support for every platEncID: https://github.com/fonttools/fonttools/blob/main/Lib/fontTools/misc/encodingTools.py#L17-L44