Fixes T5233.

• The mail adapter API currently expects plain addresses (like a@b.com) in addTos(), and some adapters can not accept fancy verbose addresses (like "name" <a@b.com>).
• When we try to send error email, we pass the entire "From" header into the API. This is incorrect.
• Since it would be nice to make this just work in the future, fix it inside the API.
• Specifically, this is reached with: send email -> generates error -> we try to send you an email back -> we send it to your "From" -> some mailers choke on the fancy name if you have one.

Processed an errorneous email with a fancy "From", got a response error.