Calendar component: broken event.date processing in Storybook

[sergei-maertens]

Providing a disabled event does not seem to be resulting in the disabled styles and behaviour being applied.

I'll check if I can add a regression test and fix

[sergei-maertens]

I dug into this for a bit and was at least able to localize the problem - it only applies in Storybook (https://nl-design-system.github.io/utrecht/storybook-react/index.html?path=/story/react-calendar--default)

• There is an existing test which passes correctly (https://github.com/nl-design-system/utrecht/blob/main/packages/component-library-react/src/Calendar/Calendar.test.tsx#L70)
• The component expects the shape {date: string, ...}, but in storybook it actually receives a Date instance. Somewhere there is some conversion happening between the events arg which uses strings and the events prop that actually ends up in the component
• I was mistakenly passing Date instances in our own component, which is why it didn't work in our storybook. Fixing that confirmed that at least with Storybook 6.5 the behaviour is as expected.

I will create a separate issue for the confusing API of the calendar.