Remove the old style argument for hilti loader

We changed the format of the hilti dataset, and hence the loader was changed to offer both new and old format of the dataset. As the format of the dataset was our decision, we can safely remove the old style format.

Locate the Hilti dataset loader and trace the argument that selects the old format; the issue does not name a file or test. Remove the old-format compatibility path and argument, then run the loader's existing tests or dataset-loading checks to confirm the current format still works.

Written by the indexing model from the issue text.