[Wi-Fi] Remove @Ignore tag in ConfigureWifiEntryFragmentTest

Remove the @Ignore tag in ConfigureWifiEntryFragmentTest, and add a fake NetworkDetailsTracker to pass test.

Bug: 151696220
Test: Run make RunSettingsRoboTests ROBOTEST_FILTER=ConfigureWifiEntryFragmentTest
Change-Id: Icf06d27030fa2c68d3c2bee03beb583592beb599

src/com/android/settings/wifi/ConfigureWifiEntryFragment.java

@@ -71,7 +71,8 @@ public class ConfigureWifiEntryFragment extends InstrumentedFragment implements
     private Button mSubmitBtn;
     private Button mCancelBtn;
     private WifiEntry mWifiEntry;
-    private NetworkDetailsTracker mNetworkDetailsTracker;
+    @VisibleForTesting
+    NetworkDetailsTracker mNetworkDetailsTracker;
     private HandlerThread mWorkerThread;
 
     @Override