Business Emailer/Notify API: Send out email to the valid emails even when 1 or more others are invalid

Currently when we send out an email to the notify-api it returns a 400 if any of the recipients have an invalid email. The validation used is more strict than what is implemented for filings so it is possible to put in an email that passes the filing validation and then causes this error when the email is sent. This means no emails will be sent even if there are other valid recipients.

Need to discuss if this should be handled differently and if we should mirror the notify api validation or if we should silently ignore invalid emails.

Example:
Registration filed in dev (FM1169819) has a proprietor with an invalid email (a@a.aba) according to the notify-api. Now its registration email is not being sent even though its contact point email is valid