Add help tooltip to dataset type

Add a tooltip help icon to the dataset type to explain what "base" since the user may not know it.  At the same time, be thorough and describe tabular as well by mentioning it's a common table format csv/excel or however you like to describe it.

<img width="1192" height="1918" alt="Image" src="https://github.com/user-attachments/assets/b149f04d-b4ce-4166-9936-a88346c50af6" />