Write a function processBatch that splits an array of strings into batches of 10, saves each batch via the Saver interface, and upon success, sends a notification via the Notifier interface.

The function splits the input slice of strings into batches of 10 elements, saves each batch using Saver.Save, and upon successful saving, sends a notification via Notifier.Notify. If an error occurs at any step, the function returns it.