kits: do not remove duplicates in link libraries

On linux, the TBB_LIBRARY_DEBUG and TBB_LIBRARY_RELEASE are the same and they are both in the list as

optimized;${TBB_LIBRARY_RELEASE};debug;${TBB_LIBRARY_DEBUG}.

Removing duplicates removes one, breaking the syntax which expects a library after each keyword.

Backport: paraview/release