Adapt OperationsService for NextcloudClient

Signed-off-by: ZetaTom <70907959+ZetaTom@users.noreply.github.com>

app/src/main/java/com/owncloud/android/services/OperationsService.java

@@ -30,6 +30,7 @@ import android.util.Pair;
 import com.nextcloud.client.account.User;
 import com.nextcloud.client.account.UserAccountManager;
 import com.nextcloud.common.NextcloudClient;
+import com.nextcloud.java.util.Optional;
 import com.nextcloud.utils.extensions.IntentExtensionsKt;
 import com.owncloud.android.MainApp;
 import com.owncloud.android.datamodel.ArbitraryDataProvider;