This change introduces scoped slots to render tooltips of stacked column
charts so it doesn't require passing a `formatTooltipText` function.

Instead they rely on the tooltip component slot to customize a tooltip.

It allows for the tooltip title and content to be changed independently.

feat(GlStackedColumnChart): Simplify chart tooltip API

See merge request !4990



Merged-by: Thomas Hutterer <thutterer@gitlab.com>
Approved-by: Rudy Crespo <rcrespo@gitlab.com>
Approved-by: Thomas Hutterer <thutterer@gitlab.com>
Reviewed-by: Miguel Rincon <mrincon@gitlab.com>
Reviewed-by: Thomas Hutterer <thutterer@gitlab.com>
Reviewed-by: Rudy Crespo <rcrespo@gitlab.com>
Co-authored-by: Miguel Rincon <mrincon@gitlab.com>

# [108.7.0](v108.6.0...v108.7.0) (2025-02-26)

### Features

* **GlStackedColumnChart:** Simplify chart tooltip API ([837c6386](837c6386))