Remove embedded & document launch always restrictions from a bubble

* No longer need the embedded flag as of ag/9341444
* Instead of requiring the app to specify documentLaunchMode=always we'll
  apply the relevant intent flags to force that behaviour
* Adds a new param to include a "fillInIntent" which can adjust the
  flags on the PendingIntent.

Bug: 138325285
Test: manual with BubblesTest (removed the flags in the test app, things
      should still bubble)
Test: atest NotificationManagerTest (needs CTS CL)
Change-Id: I08de491fc89d8182f2b2a7df95c985d8be847aab