Remove comment and guests option from Invitations UI

[miaulalala]

• Resolves: Calendar invitation response (guests and comment) not processed #23927

Summary

Sabre doesn't support comments and guests. As such, these values are never passed on to the backend and are never stored anywhere. For the moment, the only solution is to remove the option completely.

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
  • Remove comment and guests option from Invitations UI #35761
• Backports requested where applicable (ex: critical bugfixes)

[miaulalala]

/backport to stable25

[miaulalala]

/backport to stable24

[miaulalala]

/backport to stable23

[juliusknorr]

Seems reasonable

[PVince81]

/rebase

[miaulalala]

Drone failure is our old friend files sharing acceptance

[DaphneMuller]

Hello!
Thank you for your work on this! I noticed that your PR still has the label 'documentation'. I'm not sure if you already had a look at the documentation for your PR, but at Nextcloud we strive to document changes that affect other app developers or other admins before the release takes place, and I'm pinging you with the hope to get this done.

Are you familiar with our documentation process already?
Changes that affect app developers should be documented here:
https://docs.nextcloud.com/server/27/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_27.html

Changes that affect administrators should be documented here:
https://docs.nextcloud.com/server/latest/admin_manual/release_notes/upgrade_to_27.html

While I understand sometimes it's handy to merge fast to get your changes in, it would be great if next time you could try to add the documentation before merging. You can find more information on that here:
https://docs.nextcloud.com/server/27/developer_manual/prologue/compatibility_app_ecosystem.html#documentation-procedures-of-changes-that-affect-app-developers

If all your documentation efforts are done, please remove the label 'pending documentation' and check the checkbox in your opening note and I'll stop bugging you :)

Many thanks in advance and thanks again for your work!