UX/UI - Improve dataset select modal view

[abujeda]

Description

The Zenodo and Dataverse dataset select UI requires review and improvement.
Maybe upadte the UI to make it closer to the file view.

Technical Notes:

Zenodo Template: https://github.com/IQSS/ondemand-loop/blob/main/application/app/views/connectors/zenodo/_dataset_select_form.html.erb
Dataverse Template: https://github.com/IQSS/ondemand-loop/blob/main/application/app/views/connectors/dataverse/_dataset_select_form.html.erb