Listen to correct intents in UserTracker

In order to properly track added/removed work profiles, we were looking
at the wrong intents.

AVAILABLE/UNAVAILABLE are only for when QUIET_MODE
changes (from launcher or tile). We still keep these, as it means that
the flag value has changed and it may be useful for consumers.

Test: manual, add and remove work profile
Test: atest UserTrackerImplTest
Fixes: 232809563
Change-Id: I6c86d67c5413c5e8cd84221ffa552e9f873f7274