Find a new accessible way to display past events in the calendar grid

[GVodyanov]

Is your feature request related to a problem? Please describe.

Currently, what we do is display past events as having lower opacity than future events, this is great for letting the user know where they are navigating, but this isn't accessible, and will be rightfully removed by #8019

Describe the solution you'd like

It would be a bit of shame to see the feature go, so we should find some new accessible way to display past events.

Describe alternatives you've considered

No response

Additional context

No response

[kra-mo]

I'm not sure. I've seen opacity used for cancelled or pending events before, but I cannot find another calendar which uses opacity for past events. Having the current date/time displayed prominently (which we do) should be enough for the initial view and when the user navigates manually, I don't really see the added value.

[kra-mo]

To be fair, we display the current date/time clearly only in some cases. There are views where it could be improved, for example, list view or the time in week view. But then I think it would be better to improve that and drop the opacity.