haskell-generic-builder: disable library-for-ghci by default

This commit disables the library-for-ghci flag passed to
`Setup configure` in the Haskell generic-builder.nix file.

This stops the HSfoo.o file from being built.  Building this
HSfoo.o file caused doctest to take an extremely long time
to load dependencies when running.

This is a follow-up from https://github.com/NixOS/nixpkgs/pull/58743.