Allow NotificationAssistantService to suggest smart actions

Here is the flow:
NAS generates Adjustment -> NMS convert this to RankingUpdate ->
SystemUI.NotificationListener receives the RankingUpdate in either
onNotificationPosted / onNotificationRankingUpdate (Depend on does NAS
provides the adjustment before the notification is en-queued) ->
NotificationEntryManager determines the need of reinflation ->
NotificationInflater inflates / reinflates the view with these
extra bits like smart actions.

Note: We do re-inflation here as simply adding a button to the existing
notification view seems problematic. For example, if the original
notification does not have any action, we will need to inflate the
template with the action container.

Screenshot:
https://hsv.googleplex.com/5731489463402496

Test: atest SystemUITests
Test: atest com.android.server.notification.NotificationAdjustmentExtractorTest
Test: Modify ExtServices to provide adjustment in
      createEnqueuedNotificationAdjustment, post a notification with
      a entity in a sample app, observed the notification is updated.
      (Testing the onNotificationPosted flow)
Test: Modify ExtServices to provide adjustment in onNotificationPosted
      by calling adjustNotification. Post a notification with
      a entity in a sample app, observed the notification is updated.
      (Testing the onRankingUpdated flow)
Test: Repeat the above test, but explicitly make the RowInflaterTask
      slow by inserting Thread.sleep. This can test the onRankingUpdated
      flow when the row is not yet inflated.

BUG: 110527159

Change-Id: I98aee3ac62f60b189ea92ac9fc000127325dfead