[Notif] Auto-promote notifications ealier in the pipeline.

The existing PromotedNotificationsProvider class that automatically
promotes certain notifications for testing purposes is only triggered at
the end of the notification pipeline, after rendering has finished. This
works for the status bar chips, but doesn't work for other notification
promotion features like higher ranking.

This CL re-works PromotedNotificationsProvider to:
1) Happen earlier in the notif pipeline so it can be used by other
   promotion features
2) Changes how notifications are marked as auto-promoted. In this CL,
   FLAG_PROMOTED_ONGOING is set to true so that all other parts of the
   pipeline can just check `Notification.isPromotedOngoing()` and they
   don't need to worry about whether a notification was promoted via the
   standard criteria or automatically promoted.

It also renames the provider + associated classes to
AutomaticPromotionCoordinator.

Bug: 364653005
Flag: com.android.systemui.promote_notifications_automatically
Test: Send a notification that should be auto promoted -> verify it gets
promoted and has a status bar chip

Change-Id: I159f44d6f56fbfbeb48a1a002df338c0c6742d26