No not use internal-API package monitor

The GrantPermissionsActivity only needs to know when the app is removed.
All the other functionality of the internal package monitor is not
needed. Hence we can just implement a dramatically simpler package
monitor.

Test: uninstalled package while the app was asking for permissions
Bug: 110953302
Change-Id: I943fe52dcf58429eb193709b3677bca66ea46456