Stylus Metrics: Switch to non-bootstrap statslog library

Now that libinput is no longer run in a bootstrap process,
we can switch the stats logging library to the standard
version. This version is host supported, so we now also
remove the `#ifdef __ANDROID__` include guards.

Test: m checkinput
Test: flash to device, run `statsd_testdrive 718`, then
  trigger stylus prediction → reported metrics are present
  and reasonable

Bug: 311066949

Change-Id: I04e6f6906e556f4f5a71b711c6ef29d8aa6f3501