Add a key for reading avoid bad Wi-Fi from carrier config

This change introduces a new key in the carrier configuration to allow
for better control over avoid bad Wi-Fi on a per-MVNO basis.
It migrates the logic for reading the "avoid bad Wi-Fi" setting from
device resources to the carrier configuration.

Flag: android.net.platform.flags.avoid_bad_wifi_from_carrier_config
Bug: 410976315
Test: atest ConnectivityCoverageTests:android.net.connectivity.com.android.server.connectivity.MultinetworkPolicyTrackerTest
Test: atest CtsNetTestCases:android.net.cts.ConnectivityManagerTest
Change-Id: Ide0fd1e21b7590f42a43cf709767481a73c1e4eb