Include donor email in an administrator gift notice

For GiveCampus school settings.

Use the protected $ADMIN_ONLY_PROJECT_NOTIFICATION_SECTION$ in Gift Notification - Campaign. It includes Donor Email from payer_email along with name and gift details, and appears only for recipients permitted to view donor details. No separate donor-email token appears in the standard SFP token list; preserve the permission check rather than adding an invented token.