"todo-mvp-rxjava" Possible to create empty task

When trying to create a task without name Snackbar appears and save not happening. But if you create a task, and then try to edit, put there an empty name, then the task is being saved with an empty name.

Start by reproducing the empty-name flow in the todo-mvp-rxjava sample, comparing task creation with editing an existing task. Done means editing cannot save a task with an empty name, matching the existing creation behavior.

Written by the indexing model from the issue text.