[WifiTrackerLib] Use WifiInfo RSSI for connected entry

Use the rssi from WifiInfo instead of relying on the scan result rssi if
we're connected. This fixes connected entries disappearing due to missed
scans, since the rssi from WifiInfo will prevent the entry from being
marked as unreachable.

Bug: 152623244
Bug: 151344151
Test: manually verify RSSI is being updated in wifi picker
Change-Id: Iefe282b1a9d9ec5fc5706e9095a65b9c7dd5fe12
5 files changed