Steps to replicate the issue (include links if applicable):

• Set a disabled language like (zh-hant) in https://meta.wikimedia.org/wiki/Special:TranslatorSignup

What happens?:
https://zh.wikipedia.org/wiki/Special:Diff/78667515

What should have happened instead?:
This notification should not be sent because zh-hant has long been disabled and cannot be translated.

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):
Perhaps TranslatorSignup should warn the user that a disabled language is selected, or even hide the disabled language?