Expose calls to get the inset sensitivity for the calling user

- Launcher is a per-user process so we should only use the per-user
  settings calls (since it doesn't hold INTERACT_ACROSS_USERS)

Bug: 231648761
Bug: 269392826
Test: Unable to reproduce 269392826, but verified this doesn't
      break existing paths to adjust the insets
Change-Id: I4dfaed2b393e44e0455448222c997facbb3f3116