Limit maximum date to today in calendars

[apata]

Changes

Limits maximum date in calendars to today.

Tests

• Tests added

Changelog

• This PR does makes a user-facing change, but the change is very small

Documentation

• This change does not need a documentation update

Dark mode

• The UI has been tested both in dark and light mode

[ukutaht]

The design principle we've landed on is that everything in the dashboard should be scoped to the timezone of the site itself, ignoring the client's time zone completely. So we should be limiting the datepicker to "today" in the timezone that the site is configured.

With this implementation the "today" limit will change depending on the time zone I set my computer to. It's slightly confusing to me because toISOString should make it UTC but the calendar library is probably parsing it back in local timezone? Anyways, in this example I set my machine to NZ summer time (where "now" is 31st Oct) while the site stayed in Tallinn time (where "now" is 30 Oct). I would expect the date picker to limit to 30 Oct but it's 31st:

Forcing it to "today" in UTC would also be wrong because not all sites are in UTC. I think the maxDate needs to take the timezone of the site into account somehow.

[apata]

The design principle we've landed on is that everything in the dashboard should be scoped to the timezone of the site itself, ignoring the client's time zone completely. So we should be limiting the datepicker to "today" in the timezone that the site is configured.

Thanks for pointing it out, @ukutaht! It should be fixed now.

[github-actions]

Preview environment👷🏼‍♀️🏗️
PR-4746