fix(CalDAV): remove UNKNOWN from room / resource consideration

[miaulalala]

• Resolves: New and updated appointments are not sent via e-mail calendar#5706

Summary

The UNKNOWN CU type might be given to legitimate ATTENDEEs of an event.

Filtering only for specific CU types will allow for actual attendees to still receive invitations. There is nothing in the RFC that specifies that UNKNOWN is a "thing".

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[miaulalala]

/backport to stable29

[miaulalala]

/backport to stable28

[miaulalala]

/backport to stable27

[tcitworld]

What about nextcloud/calendar#5706 (comment) ?

[miaulalala]

What about nextcloud/calendar#5706 (comment) ?

We could, but nobody has complained about the email notifications (yet) so I'm hesitant to touch it.

[miaulalala]

/backport to stable29

[miaulalala]

/backport to stable28

[miaulalala]

/backport to stable27

[backportbot]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b backport/44938/stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick a28f2647

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/44938/stable27

Error: Failed to create pull request: Validation Failed: {"resource":"PullRequest","code":"custom","message":"A pull request already exists for nextcloud:backport/44938/stable27."}

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[backportbot]

The backport to stable28 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable28
git pull origin stable28

# Create the new backport branch
git checkout -b backport/44938/stable28

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick a28f2647

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/44938/stable28

Error: Failed to create pull request: Validation Failed: {"resource":"PullRequest","code":"custom","message":"A pull request already exists for nextcloud:backport/44938/stable28."}

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.