List columns for all elements in a workbook

This endpoint retrieves all columns in a workbook for all element in the workbook. ### Usage notes - Retrieve the **workbookId** by calling the [/v2/workbooks](https://help.sigmacomputing.com/reference/list-workbooks) endpoint. ### Usage scenarios - **Data exploration:** Enable users to explore the data structure of a workbook element, facilitating deeper analysis and understanding. - **Integration tasks:** Useful for developers integrating Sigma with other tools that need to know the data structure to map data accurately. ### Best practices - Use this endpoint when setting up interfaces that require specific knowledge about the data structure.