Update Sending Settings Changed Notifications

This CL updates piping settings changed notifications from the
ContextHub HAL to CHRE by:
- Supporting multi-user location settings by sending a notification
on a user change
- Sending a microphone access notification on a ContextHub HAL reset

Bug: 183218234
Test: Test prerequisites -  have 2 users (Owner, Guest) on device,
default location settings on owner is enabled.
- Change location setting to 'disabled' on Owner, observe that the
settings change is propagated (via a log msg).
- Change user to Guest, observe a location enabled notification
(via a log msg)
- Permutations of the above, observe correct behavior via log msgs.
- Repeat on a different device for a consistency check

Change-Id: Ib2bc7cac37ea4a0e0acdf0930df3a926b0efb1c2