Defer applying gestural nav until the device is provisioned and user is setup

- When SystemUI detects that the device is not provisioned (first boot) or
  the user is not setup (multiuser), we revert to 3button until both
  states are true (usually after setup wizard).  This only happens when
  the default navigation mode of the device is gestural.

Bug: 130185871
Test: Setup a new device and ensure the nav mode is 3 button during SUW

Change-Id: Ia243aa9ebd4a1198b2e06020367625936d1d3f3d