Kiwi Android crashes when opening synced tabs

### Which version of floccus are you using?

4.14.0

### Sync method

{"label"=>"WebDAV"}

### Which browser are you using? In case you are using the Android App, specify the Android version please.

101.0.4591.48

### Which version of Nextcloud Bookmarks are you using? (if relevant)

_No response_

### Which version of Nextcloud? (if relevant)

_No response_

### What kind of WebDAV server are you using? (if relevant)

Synology NAS WebDAV server

### Describe the Bug

1) With WebDAV, I sync 5 tabs from Google Chrome on my laptop and the sync completes. Sync type (two-way/one-way) seems irrelevant.
2) On my Android device, I manually (or automatically) trigger a sync with the Floccus Kiwi browser extension.
3) Kiwi browser tries to open the 5 new tabs all at once, I see them in the tab bar/list for a split second, then the app crashes. No debug logs are available upon restart, and all tabs that appeared are gone upon reopening.
4) The WebDAV server still includes a stale .xbel.lock file, so no other syncs from any device work until I manually delete it.

### Expected Behavior

The Kiwi Android browser syncs tabs the same way Google Chrome Mac does.

### To Reproduce

See bug description.

### Debug log provided

- [ ] I have provided a debug log file