Swiping a notification should not mark message as read

Current behaviour:
Notification "mark as read" clicked: notification removed, related buffer marked as read
Notification swiped away: notification removed, related buffer marked as read

Expected behaviour:
Notification "mark as read" clicked: notification removed, related buffer marked as read
Notification swiped away: notification removed, no change to buffer

The "expected behaviour" is aligned with how the native android text message or email clients operate.