WifiConfigStore: Remove all usage of WifiMigration.loadFromStore

In preparation of moving away from this API surface to a different
mechanism.

Bug: 149418926
Test: atest com.android.server.wifi
Test: Device boots up and connects to wifi networks.
Change-Id: I530d79138ea9219eace686b736e843c4c2d37187
29 files changed
tree: 64a85b168a89cddeccf31dad6c0ff8b6d351f2ee
  1. apex/
  2. service/
  3. PREUPLOAD.cfg