WifiManager: Send list of matching scan results for network request

Change the arguments for the onMatch() callback to return a list of
|ScanResult| instead of |WifiConfiguration|. This allows the settings UI
team to reuse the existing infrastructure used for presenting list of networks in
the wifi picker UI.

Bug: 113878056
Test: ./frameworks/base/wifi/tests/runtests.sh
Change-Id: Ic7e0665bbef35a52df77be4d3c0574b01e0c8193