[menu] Discuss the need for "single" and "multiple" select variants

[Diaan]

in storybook there are "single" and "multiple" select stories. This is not an option in Figma (yet) we don't really know what the use case for these is, how it differs from a regular select / combobox. We need to have some background info such as use cases/ usages/ patterns to be able to write proper documentation if we actually need those variants. https://storybook.sanomalearning.design/?path=/story/components-menu-button--single-select https://storybook.sanomalearning.design/?path=/story/components-menu-button--multi-select