fix(caldav): limit property length

[miaulalala]

Summary

Make longer properties searchable for the property index

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 stable30

[miaulalala]

/backport to stable29

[miaulalala]

/backport to stable28

[come-nc]

Won’t that apply to event description or stuff like that which might need more than 255 chars?

[miaulalala]

Won’t that apply to event description or stuff like that which might need more than 255 chars?

it's just the search index - the data itself is stored in oc_calendar_objects