fix(caldav): limit vevent size

[SebastianKrupinski]

Resolves: Event size limit

[SebastianKrupinski]

/backport to stable29

[SebastianKrupinski]

/backport to stable28

[SebastianKrupinski]

/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/46315/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 247fbb55

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/46315/stable27

Error: Failed to push branch backport/46315/stable27: fatal: could not read Username for 'https://github.com': No such device or address

---

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