WifiBackupRestore: Some cosmetic cleanups

Changes in the CL:
1. Consolidate the logic in supplicant backup migration to skip
enterprise networks during restore.
2. Create a helper method to restore networks once they're parsed out
from the backup data.

BUG: 28967335
Change-Id: I94cd5530afa5dc953cb8914c03ae7d554e0f182b
TEST: Unit-tests
2 files changed
tree: 14f2b81aab7ce756f1b84a98ec1499b2b968877a
  1. service/
  2. tests/