Honor per-user setting for assist gesture and long-press home

These are per-user settings, we need to fetch them as such.

Bug: 189475831
Test: Enable and disable corner gesture, switching between users. Ensure
      that current user's setting is honored.
Change-Id: I5e3587ddb0fa4bd1ef68488485d73641e0582d2f
Merged-In: I5e3587ddb0fa4bd1ef68488485d73641e0582d2f