Hi,
that space is added by the DataTables library (it is necessary when the Pagination is active). It does however not make sense on small tables like yours.
The fix is easy though, as you seem to have disabled the DataTables features for that table anyway: Just disable the usage of the DataTables library for that table entirely. (Not just the individual features, but the complete library. The checkbox for that is right above those other ones.)
Best wishes,
Tobias