Migrate to androidx namespace for support library.

Fixes: 77483560
Test: build KitchenSink, deploy and test through fragments
Test: build and launch UxRestrictionsSample
Change-Id: I539c71464f5a486c9a9373bbbcae8ac14d24e477
diff --git a/tests/EmbeddedKitchenSinkApp/src/com/google/android/car/kitchensink/notification/NotificationFragment.java b/tests/EmbeddedKitchenSinkApp/src/com/google/android/car/kitchensink/notification/NotificationFragment.java
index 5f88259..7a26f93 100644
--- a/tests/EmbeddedKitchenSinkApp/src/com/google/android/car/kitchensink/notification/NotificationFragment.java
+++ b/tests/EmbeddedKitchenSinkApp/src/com/google/android/car/kitchensink/notification/NotificationFragment.java
@@ -12,12 +12,13 @@
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
-import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.Button;
 
+import androidx.fragment.app.Fragment;
+
 import com.google.android.car.kitchensink.KitchenSinkActivity;
 import com.google.android.car.kitchensink.R;