[Wi-Fi] Apply WifiTrackerLib objects in Wi-Fi Slice

This change uses WifiTrackerLib's WifiPickerTracker & WifiEntry
to replace SettingLib's WifiTracker & AccessPoint.

This change includes

1. WifiScanWorker has the callbacks similar to a lifecycle component
   but it's not a lifecycle component. Let WifiScanWorker implements
   LifecycleOwner and provides #getLifecycle() for WifiPickerTracker.

2. Remove captive portal related code because WifiEntry#connect will
   handle captive portal login if it's necessary.

3. Create WifiSliceItem to wrap WifiEntry because WifiEntry is an
   abstract object and it does not provide copy constructor.
   Without copy construcor, Wi-Fi Slice may show unexpected information
   when a WifiEntry is updated.

Bug: 155613549
Bug: 152571756
Test: make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.wifi.slice
      make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.wifi
Change-Id: I2d66ea4905daca3244ec4cf8f2935cda817480b1

src/com/android/settings/wifi/slice/ContextualWifiScanWorker.java

@@ -18,7 +18,6 @@ package com.android.settings.wifi.slice;
 
 import android.content.Context;
 import android.net.Uri;
-import android.os.SystemClock;
 
 import com.android.settings.slices.SliceBackgroundWorker;
 
@@ -27,44 +26,12 @@ import com.android.settings.slices.SliceBackgroundWorker;
  */
 public class ContextualWifiScanWorker extends WifiScanWorker {
 
-    private static long sVisibleUiSessionToken;
-    private static long sActiveSession;
-
     public ContextualWifiScanWorker(Context context, Uri uri) {
         super(context, uri);
     }
 
-    /**
-     * Starts a new visible UI session for the purpose of automatically starting captive portal.
-     *
-     * A visible UI session is defined as a duration of time when a UI screen is visible to user.
-     * Going to a sub-page and coming out breaks the continuation, leaving the page and coming back
-     * breaks it too.
-     */
-    public static void newVisibleUiSession() {
-        sVisibleUiSessionToken = SystemClock.elapsedRealtime();
-    }
-
-    static void saveSession() {
-        sActiveSession = sVisibleUiSessionToken;
-    }
-
-    @Override
-    protected void clearClickedWifiOnSliceUnpinned() {
-        // Do nothing for contextual Wi-Fi slice
-    }
-
-    @Override
-    protected boolean isSessionValid() {
-        if (sVisibleUiSessionToken != sActiveSession) {
-            clearClickedWifi();
-            return false;
-        }
-        return true;
-    }
-
     @Override
     protected int getApRowCount() {
         return ContextualWifiSlice.getApRowCount();
     }
-}
+}