Fix empty network scan result

Settings use TelephonyScanManager.NetworkScanCallback to scan, and its
onComplete() could happens before onResults().

We will change Settings to fix.

Fix: 338986191
Test: manual - on NetworkSelectSettings
Test: unit test
Change-Id: If41d957f916a99eacc1becb6b460e58722a4dca7
Merged-In: If41d957f916a99eacc1becb6b460e58722a4dca7
4 files changed