Fix NPE when getting managed profile info.

- There can be a race condition where the cached profile user ids
  aren't yet updated but the actual user has already been removed.
  Ignore these users when computing the quiet profile users.

Bug: 67932220
Test: Add/remove a work profile and launch an app
Change-Id: I8888d30e431ca4ffdacc28cc15a80a2deaa23d10