Add initial WifiTracker2 into WifiSettings2

Added WifiTracker2 into WifiSettings2, and made WifiSettings2 listen to
wifi state change callbacks from WifiTracker2 to update the WifiEntry
list.

Test: atest WifiSettings2Test, build and visual verification
Bug: 70983952

Change-Id: Ieda699d05d350553a526f9536de58937c49c7280
1 file changed