This update ensures that stacked bar charts created within Odoo spreadsheets automatically include a total line, mirroring the standard behavior of charts in the main Odoo graph view. This improves consistency and makes spreadsheet charts more intuitive for users who are familiar with Odoo's charting capabilities. It addresses a visual discrepancy between spreadsheet and standard charts.

## Description

When inserting a stacked bar graph view into a spreadsheet, enable
showTotalLine on the generated chart definition.

This keeps inserted spreadsheet charts aligned with the Odoo graph view,
where stacked bar charts display the Sum line by default.

Task: [5886277](https://www.odoo.com/odoo/project/2328/tasks/5886277)