Fix lumisections/joint_lumisection_ranges endpoint ignoring dataset_name when fetching oms lumisections

[gabrielmscampos]

When the DC expert recovers DCS bits in Offline Run Registry, those entries aren't updated in the OMS online dataset but instead in the specific dataset the operation was targeted.

Right now, if you inspect the "OMS LUMISECTIONS" tab for an Offline dataset, the DCS bits are different from the "BOTH" tab.

[nothingface0]

For completion and future reference, this endpoint (joint_lumisection_ranges) is an aggregate of oms_lumisection_ranges and rr_lumisection_ranges.

Those are used mostly in the frontend, in the modal that appears when clicking LS (next to Manage) for a specific run.

The OMS LUMISECTIONS button uses oms_lumisection_ranges, the RR LUMISECTIONS uses the rr_lumisection_ranges and the BOTH button uses the joint_lumisection_ranges. All calls to each endpoint from the frontend are passed the dataset argument, but the joint_lumisection_ranges was ignoring it, always using online instead. This was probably not the intended functionality.