Messaging: Rename androidx.appcompat.mms

* Someone apparently decided to "Replace-In-Files" these before, but
  they are not correct according to the folder structure
* Since it is just annoying to read the code in AS when it does not
  match the folder, change the package name back

Change-Id: Iea5c51aeb9e1f5b650a1009348065c7c38cddbeb

src/com/android/messaging/ui/appsettings/PerSubscriptionSettingsActivity.java

@@ -29,10 +29,10 @@ import android.preference.Preference.OnPreferenceClickListener;
 import android.preference.PreferenceCategory;
 import android.preference.PreferenceFragment;
 import android.preference.PreferenceScreen;
+import android.support.v7.mms.MmsManager;
 import android.text.TextUtils;
 import android.view.MenuItem;
 
-import androidx.appcompat.mms.MmsManager;
 import androidx.core.app.NavUtils;
 
 import com.android.messaging.Factory;