Fixes T8524, T8550. These were both missing "subscribers" and Phriction was also the only application with no "other".

• Project
  • • set user A to notify only for project subscriber changes
    • made a project with user A
    • subscribed user B to project
    • verified notification sent to user A
    • used ./bin/mail to make sure no mail was sent to user A because "This mail has tags which control which users receive it, and this recipient has not elected to receive mail with any of the tags on this message (Settings > Email Preferences)."
  • Phriction
    • set user A to notify only for phriction document subscriber changes
    • made a document with user A
    • subscribed user B to document
    • verified notification sent to user A
    • used ./bin/mail to make sure no mail was sent to user A because "This mail has tags which control which users receive it, and this recipient has not elected to receive mail with any of the tags on this message (Settings > Email Preferences)."
    • observed option for "other" in email preferences