Make shared caldav calenders accessible under one URL

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Is your feature request related to a problem? Please describe.
Shared calendars on the same Nextcloud instance do have user dependent caldav URLs, e.g.:

• user1 (Owner): https.///remote.php/dav/calendars/user1/mycalendar
• user2: https.///remote.php/dav/calendars/user2/mycalendar_shared_by_user1
• user3: https.///remote.php/dav/calendars/user3/mycalendar_shared_by_user1

This means that user1 cannot share the link to a specific caldav object (e.g. https.///remote.php/dav/calendars/user1/mycalendar/1234.ics).

Background is a small webapp I'm developing, were a scanned QR code including a caldav URL is used to undone a task for a shopping list.

Describe the solution you'd like
It would be great if https.///remote.php/dav/calendars/user1/mycalendar is also directly accessible by user 2 and user3. Currently, a 404 is returned.

No files or tests are named. Start by tracing the handler for /remote.php/dav/calendars/... and how shared-calendar access is authorized. Done means permitted users can use the owner's calendar URL for shared objects while unauthorized users remain blocked.