Accept/decline/tentative actions shown for (read-only) shared calendar

[ChristophWurst]

Steps to reproduce

1. As user A create a calendar as user A
2. As user A Share the calendar read-only with user B
3. As user B click on the event

Expected behavior

There is nothing to click or change for user B.

Actual behaviour

User B can click Accept/Decline/Tentative on the read-only event.

In contrast I can update participation on the copy in my personal calendar.

If the calendar is shared with write permissions, the update works, but I wonder if we shouldn't hide the buttons as well. This might be debatable.

Calendar app version

3.2.2

CalDAV-clients used

No response

Browser

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Client operating system

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Server operating system

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Web server

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Database engine version

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PHP engine version

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Nextcloud version

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Updated from an older installed version or fresh install

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List of activated apps

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Nextcloud configuration

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Web server error log

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Log file

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Browser log

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Additional info

This is an edge case of the new feature #144. cc @st3iny

[st3iny]

If the calendar is shared with write permissions, the update works, but I wonder if we shouldn't hide the buttons as well.

I tested this edge case and it works fine. The response is propagated correctly to both events if either of the two is updated.