[RailsDevs] Don't retry failed jobs if the recipient is inactive

Sending emails via Postmark can raise a Postmark::InactiveRecipientError error, indicating that the recipient has disabled emails from RailsDevs. But because the job failed Sidekiq is retrying it over and over again.

A PR addressing this issue should:
• Catch Postmark::InactiveRecipientError errors in ApplicationJob and not queue them for retry