Fix crash when no Bluetooth feature in Settings

- Move PreferenceGroup init method out of isAvailable() condition,
  then PreferenceGroup will not be null.
- Update getAvailabilityStatus(), since the controller now may have usb
  and dock.

Bug: 110712414
Test: make -j42 RunSettingsRoboTests
Change-Id: I4d85a42c26fb20d319e7321177b271933be3fdb0

src/com/android/settings/connecteddevice/SavedDeviceGroupController.java

@@ -73,10 +73,10 @@ public class SavedDeviceGroupController extends BasePreferenceController
 
     @Override
     public void displayPreference(PreferenceScreen screen) {
-        if (isAvailable()) {
-            mPreferenceGroup = screen.findPreference(KEY);
-            mPreferenceGroup.setVisible(false);
+        mPreferenceGroup = screen.findPreference(KEY);
+        mPreferenceGroup.setVisible(false);
 
+        if (isAvailable()) {
             final Context context = screen.getContext();
             mBluetoothDeviceUpdater.setPrefContext(context);
             mBluetoothDeviceUpdater.forceUpdate();
@@ -87,7 +87,8 @@ public class SavedDeviceGroupController extends BasePreferenceController
 
     @Override
     public int getAvailabilityStatus() {
-        return mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH)
+        return (mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH)
+                || mSavedDockUpdater != null)
                 ? AVAILABLE
                 : UNSUPPORTED_ON_DEVICE;
     }