Previously SVNHelper::IsVersioned would be called (from
g_shellCache.IsVersioned) and that would try to access the WC (opening wc.db).
That could cause performance issues with SQLite, for example if accessing
a WSL-share.
Original report: https://groups.google.com/g/tortoisesvn/c/BjYlMU4Bg6A
Discussed: https://groups.google.com/g/tortoisesvn-dev/c/Ao4rtDqnEiI
