Update libkiwix with search iterator rename in libzim

Search iterator API in libzim has been shifted to use camel case naming.
This has to be accomodated in libkiwix as well.
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f