Prevent nullptr deref in SparseTensorSliceDataset

The arguments must determine a valid sparse tensor. This means that when indices are empty then the values must be empty too (and the reverse).

Also added test, by modifying existing test with empty sparse tensor to now run with an invalid sparse tensor input.

PiperOrigin-RevId: 388562757
Change-Id: Id8b54cd7c2316025b4f9a77292c8fb5344d17609