Address issue with deleting the last cell model in the DataSource

[ChrishonWyllie]

Upon deleting the last cell model in a DataSourceProvider section, it will delete the array that represents the section as well.
This is normal behavior except for when it was the last section in the entire DataSourceProvider.
Doing this will return a completely empty provider, which can cause crashes when checking the numberOfItems(in section: Int) function.

Refactor the func deleteCellItems(atIndexPaths indexPaths: [IndexPath]) to avoid doing this