Allocation of icu transliterator in removeAccents on apple fails about libkiwix

[BPerlakiH]

I have investigated this further. The issue will be fixed on the Apple side here:
kiwix/kiwix-apple#868

The reason it was failing is that we had calls to Kiwix::Manager->readOPDS() from multiple threads at the same time!

From the more detailed crash report, I can see that both Thread 1 and Thread 6 are calling the same:

[kelson42]

From first investigation, from trace, apple application is using icu73.
But we are loading icu data version 58 (https://github.com/kiwix/libkiwix/blob/main/src/tools/stringTools.cpp#L39-L49)

We do use version 73, see https://github.com/kiwix/kiwix-build/blob/main/kiwixbuild/dependencies/icu4c.py#L17. The only question is why do we use what looks like to be an outdated .dat file!?