WifiConfigManager: Retrieve all hidden networks

The current logic does not retrieve hidden networks if they're disabled.
This causes us to not scan for hidden saved networks which were disabled
due to authentication failures. And the user will not be able to see such
hidden networks in their wifi preferences window.

Bug: 68289406
Test: Unit tests
Change-Id: If66448d151f74500f45b44856546d0a3d8c8e897
2 files changed