Scan manager: Suspend scan when location is off

* Add a broadcast receiver to listen for location on/off event. When
location is off, send SUSPEND_SCAN message; when location is on, send
RESUME_SCAN message
* In handleStartScan(), suspend the scan if location is off, unless it
is a filtered scan or issued by a legacy app
* Both location on/off and display on/off events are handled in
HandlerThread, so there is no collision

Test: manual
Bug: 73485839
Change-Id: Ie7adcd91afbb95e2bd231a11ed557915583f1d6c