Support for hotspot client visibility.

Adding support for visibility into the mac address of clients that connect to an active hotspot.

Bug: 137309578
Test: sh system/connectivity/wificond/./runtests.sh
Tested manually on a Pixel 3.

Change-Id: I0845b51dc63c046df97e55bcc1c02c4610837453
Merged-In: I0845b51dc63c046df97e55bcc1c02c4610837453
10 files changed