Sidebar should remember visible/invisible status

[petrarca-arezzo]

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

The left navigation sidebar is always showing up if one is coming back to the calendar view, although it was closed (invisible) when leaving the calendar view.

Describe the solution you'd like

Nextcloud calendar should remember the visibility status of the left sidebar (opened, closed).

Describe alternatives you've considered

No response

Additional context

No response