BaseStatusBar: Inform StatusBarService if a notification is flagged spam

Without this change, if a notification that flashes the status LED is
dismissed as spam by the user, the status LED continues to blink while
the device is on standby (because the notification is not removed from
NotificationManagerService.mLights) until the next boot.

Change-Id: I30074adefa8f25cb21ae6550d523a91ebb943527